[BUGFIX] SubscriptionResumptionStorage SubscriptionInfo SetEventPath and SetAttributePath tries to Calloc(0)

[jtung-apple]

Simple fix for the case where Calloc(0) is guarded and causes a fault.

@mkardous-silabs pointed out this is an issue for rtos.

[mkardous-silabs]

tested on hardware and it fixes the fault

[github-actions]

PR #24982: Size comparison from 5ad70f6 to 873f0b0

Increases (1 build for cc32xx)

platform	target	config	section	5ad70f6	873f0b0	change	% change
cc32xx	lock	CC3235SF_LAUNCHXL	.debug_info	20194394	20194444	50	0.0
			.debug_line	2649797	2649822	25	0.0
			.debug_loc	2785922	2785969	47	0.0

Decreases (1 build for cc32xx)

platform	target	config	section	5ad70f6	873f0b0	change	% change
cc32xx	lock	CC3235SF_LAUNCHXL	.debug_ranges	280720	280696	-24	-0.0

Full report (1 build for cc32xx)

platform	target	config	section	5ad70f6	873f0b0	change	% change
cc32xx	lock	CC3235SF_LAUNCHXL		0	0	0	0.0
			(read only)	640233	640233	0	0.0
			(read/write)	204084	204084	0	0.0
			.ARM.attributes	44	44	0	0.0
			.ARM.exidx	8	8	0	0.0
			.bss	197488	197488	0	0.0
			.comment	194	194	0	0.0
			.data	1476	1476	0	0.0
			.debug_abbrev	928439	928439	0	0.0
			.debug_aranges	87352	87352	0	0.0
			.debug_frame	299840	299840	0	0.0
			.debug_info	20194394	20194444	50	0.0
			.debug_line	2649797	2649822	25	0.0
			.debug_loc	2785922	2785969	47	0.0
			.debug_ranges	280720	280696	-24	-0.0
			.debug_str	3001474	3001474	0	0.0
			.ramVecs	780	780	0	0.0
			.resetVecs	64	64	0	0.0
			.rodata	105585	105585	0	0.0
			.shstrtab	232	232	0	0.0
			.stab	204	204	0	0.0
			.stabstr	441	441	0	0.0
			.stack	2048	2048	0	0.0
			.strtab	375840	375840	0	0.0
			.symtab	255856	255856	0	0.0
			.text	532524	532524	0	0.0