[YAML] Remove GetUniqueDiscriminator since cross-talks seems to be gone now

[vivien-apple]

Problem

The GetUniqueDiscriminator method in YAML was used as a way to workaround the collisions between instances mdns advertisement on CI. Mdns advertisement are now broadcasting only onto the local interface so this method can be removed.

Change overview

• Remove GetUniqueDiscriminator

[woody-apple]

Fast tracking testing changes

[github-actions]

PR #15784: Size comparison from 2c4fb91 to 2de86ef

Increases above 0.2%:

platform	target	config	section	2c4fb91	2de86ef	change	% change
nrfconnect	all-clusters-app	nrf52840dk_nrf52840	(read/write)	1040115	1076775	36660	3.5
			bss	125828	127944	2116	1.7
			rodata	135820	141760	5940	4.4
			text	701220	729640	28420	4.1

Increases (1 build for nrfconnect)

platform	target	config	section	2c4fb91	2de86ef	change	% change
nrfconnect	all-clusters-app	nrf52840dk_nrf52840	(read/write)	1040115	1076775	36660	3.5
			bss	125828	127944	2116	1.7
			rodata	135820	141760	5940	4.4
			text	701220	729640	28420	4.1

Decreases (1 build for linux)

platform	target	config	section	2c4fb91	2de86ef	change	% change
linux	chip-tool-ipv6only	arm64	(read only)	9045876	9042340	-3536	-0.0
			.rodata	473100	472940	-160	-0.0
			.text	7694196	7691060	-3136	-0.0

Full report (22 builds for cyw30739, efr32, esp32, k32w, linux, mbed, nrfconnect, p6, qpg, telink)

platform	target	config	section	2c4fb91	2de86ef	change	% change
cyw30739	light	cyw930739m2evb_01	(read/write)	600618	600618	0	0.0
			.app_xip_area	505392	505392	0	0.0
			.bss	77908	77908	0	0.0
			.data	660	660	0	0.0
			.rodata	0	0	0	0.0
			.text	0	0	0	0.0
	lock	cyw930739m2evb_01	(read/write)	558614	558614	0	0.0
			.app_xip_area	464924	464924	0	0.0
			.bss	76412	76412	0	0.0
			.data	624	624	0	0.0
			.rodata	0	0	0	0.0
			.text	0	0	0	0.0
	ota-requestor	cyw930739m2evb_01	(read/write)	579394	579394	0	0.0
			.app_xip_area	476008	476008	0	0.0
			.bss	85780	85780	0	0.0
			.data	568	568	0	0.0
			.rodata	0	0	0	0.0
			.text	112	112	0	0.0
efr32	lighting-app	BRD4161A	(read only)	917996	917996	0	0.0
			(read/write)	128936	128936	0	0.0
			.bss	126880	126880	0	0.0
			.data	2056	2056	0	0.0
			.text	917988	917988	0	0.0
		BRD4161A+rpc	(read only)	948072	948072	0	0.0
			(read/write)	145880	145880	0	0.0
			.bss	143656	143656	0	0.0
			.data	2220	2220	0	0.0
			.text	948064	948064	0	0.0
	lock-app	BRD4161A+wf200	(read only)	987676	987676	0	0.0
			(read/write)	120432	120432	0	0.0
			.bss	118500	118500	0	0.0
			.data	1932	1932	0	0.0
			.text	987668	987668	0	0.0
	window-app	BRD4161A	(read only)	852396	852396	0	0.0
			(read/write)	126908	126908	0	0.0
			.bss	124984	124984	0	0.0
			.data	1924	1924	0	0.0
			.text	852388	852388	0	0.0
esp32	all-clusters-app	c3devkit	(read only)	953150	953150	0	0.0
			(read/write)	1392866	1392866	0	0.0
			.dram0.bss	62664	62664	0	0.0
			.dram0.data	14236	14236	0	0.0
			.flash.rodata	197048	197048	0	0.0
			.flash.text	953150	953150	0	0.0
			.iram0.text	62016	62016	0	0.0
		m5stack	(read only)	1008323	1008323	0	0.0
			(read/write)	459980	459980	0	0.0
			.dram0.bss	68184	68184	0	0.0
			.dram0.data	34080	34080	0	0.0
			.flash.rodata	225880	225880	0	0.0
			.flash.text	1002939	1002939	0	0.0
			.iram0.text	123107	123107	0	0.0
k32w	light	k32w061+release	(read/write)	693200	693200	0	0.0
			.bss	77808	77808	0	0.0
			.data	1932	1932	0	0.0
			.text	607660	607660	0	0.0
	lock	k32w061+release	(read/write)	696200	696200	0	0.0
			.bss	77744	77744	0	0.0
			.data	1972	1972	0	0.0
			.text	610684	610684	0	0.0
linux	chip-tool-ipv6only	arm64	(read only)	9045876	9042340	-3536	-0.0
			(read/write)	401521	401521	0	0.0
			.bss	43745	43745	0	0.0
			.data	1192	1192	0	0.0
			.data.rel.ro	300984	300984	0	0.0
			.dynamic	560	560	0	0.0
			.got	51816	51816	0	0.0
			.init	24	24	0	0.0
			.init_array	192	192	0	0.0
			.rodata	473100	472940	-160	-0.0
			.text	7694196	7691060	-3136	-0.0
	thermostat-no-ble	arm64	(read only)	2169572	2169572	0	0.0
			(read/write)	148625	148625	0	0.0
			.bss	65345	65345	0	0.0
			.data	1072	1072	0	0.0
			.data.rel.ro	75032	75032	0	0.0
			.dynamic	560	560	0	0.0
			.got	4216	4216	0	0.0
			.init	24	24	0	0.0
			.init_array	352	352	0	0.0
			.rodata	132996	132996	0	0.0
			.text	1818352	1818352	0	0.0
mbed	lock-app	CY8CPROTO_062_4343W+release	(read only)	6224	6224	0	0.0
			(read/write)	2350996	2350996	0	0.0
			.bss	187156	187156	0	0.0
			.data	5784	5784	0	0.0
			.text	1313596	1313596	0	0.0
nrfconnect	all-clusters-app	nrf52840dk_nrf52840	(read/write)	1040115	1076775	36660	3.5
			bss	125828	127944	2116	1.7
			rodata	135820	141760	5940	4.4
			text	701220	729640	28420	4.1
p6	all-clusters-app	default	(read/write)	2489552	2489552	0	0.0
			.bss	118736	118736	0	0.0
			.data	2696	2696	0	0.0
			.text	1447816	1447816	0	0.0
	light-app	default	(read/write)	2396728	2396728	0	0.0
			.bss	113048	113048	0	0.0
			.data	2544	2544	0	0.0
			.text	1354992	1354992	0	0.0
	lock-app	default	(read/write)	2360240	2360240	0	0.0
			.bss	112792	112792	0	0.0
			.data	2504	2504	0	0.0
			.text	1318504	1318504	0	0.0
qpg	lighting-app	qpg6105+debug	(read only)	602284	602284	0	0.0
			(read/write)	146936	146936	0	0.0
			.bss	91192	91192	0	0.0
			.data	1132	1132	0	0.0
			.text	596964	596964	0	0.0
	lock-app	qpg6105+debug	(read only)	567984	567984	0	0.0
			(read/write)	146936	146936	0	0.0
			.bss	91200	91200	0	0.0
			.data	1084	1084	0	0.0
			.text	562664	562664	0	0.0
	persistent-storage-app	qpg6105+debug	(read only)	99520	99520	0	0.0
			(read/write)	146940	146940	0	0.0
			.bss	24004	24004	0	0.0
			.data	176	176	0	0.0
			.text	94200	94200	0	0.0
telink	lighting-app	tlsr9518adk80d	(read/write)	884222	884222	0	0.0
			bss	86408	86408	0	0.0
			noinit	37160	37160	0	0.0
			text	625174	625174	0	0.0