[Broadcom] Upgrade xgs SAI to 12.3.0.3 (sonic-net#21504)

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#### Why I did it
Upgrade xgs SAI to 12.3.0.3
- 12.3.0.3: [AN/LT] Enable Microsoft AN/LT behavior

##### Work item tracking
- Microsoft ADO **(number only)**: 30861840

#### How I did it
Update sai.mk file.
#### How to verify it
Load image on DUT, all dockers and bgp are up and running.
```
admin@bjw-can-7260-8:~$ show ver

SONiC Software Version: SONiC.master-21434.746845-307d109b3
SONiC OS Version: 12
Distribution: Debian 12.9
Kernel: 6.1.0-22-2-amd64
Build commit: 307d109
Build date: Wed Jan 15 04:08:24 UTC 2025
Built by: azureuser@3a64ff00c000001

admin@bjw-can-7260-8:~$ docker ps -a
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
c15fbf0578a9 docker-snmp:latest "/usr/bin/docker-snm…" 5 minutes ago Up 5 minutes snmp
b1cc7ffd2ab5 docker-platform-monitor:latest "/usr/bin/docker_ini…" 5 minutes ago Up 5 minutes pmon
6ce287e3bfb7 docker-sonic-mgmt-framework:latest "/usr/local/bin/supe…" 5 minutes ago Up 5 minutes mgmt-framework
3fc74c056133 docker-lldp:latest "/usr/bin/docker-lld…" 5 minutes ago Up 5 minutes lldp
6523b6158c4c docker-sonic-gnmi:latest "/usr/local/bin/supe…" 5 minutes ago Up 5 minutes gnmi
e9026d1614b0 docker-router-advertiser:latest "/usr/bin/docker-ini…" 7 minutes ago Up 7 minutes radv
4b3ea684231d docker-syncd-brcm:latest "/usr/local/bin/supe…" 7 minutes ago Up 7 minutes syncd
48719dd59e90 docker-teamd:latest "/usr/local/bin/supe…" 7 minutes ago Up 7 minutes teamd
77b9db48362a docker-fpm-frr:latest "/usr/bin/docker_ini…" 7 minutes ago Up 7 minutes bgp
f76c1f67f26c docker-orchagent:latest "/usr/bin/docker-ini…" 7 minutes ago Up 7 minutes swss
d08920cae101 docker-eventd:latest "/usr/local/bin/supe…" 7 minutes ago Up 7 minutes eventd
39732f2a234a docker-sonic-restapi:latest "/usr/local/bin/supe…" 7 minutes ago Up 7 minutes restapi
93d6562535c0 docker-database:latest "/usr/local/bin/dock…" 7 minutes ago Up 7 minutes database
admin@bjw-can-7260-8:~$ show ip bgp sum

IPv4 Unicast Summary:
BGP router identifier 10.1.0.32, local AS number 65100 vrf-id 0
BGP table version 24679
RIB entries 12851, using 1644928 bytes of memory
Peers 24, using 494208 KiB of memory
Peer groups 2, using 128 bytes of memory

Neighbhor V AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down State/PfxRcd NeighborName
----------- --- ----- --------- --------- -------- ----- ------ --------- -------------- --------------
10.0.0.1 4 65200 3326 3348 24679 0 0 00:06:39 6370 ARISTA01T2
10.0.0.5 4 65200 3323 3348 24679 0 0 00:06:39 6370 ARISTA03T2
10.0.0.9 4 65200 3320 3341 24679 0 0 00:06:31 6370 ARISTA05T2
10.0.0.13 4 65200 3320 3341 24679 0 0 00:06:31 6370 ARISTA07T2
10.0.0.33 4 64001 142 3348 24679 0 0 00:06:39 3 ARISTA01T0
10.0.0.35 4 64002 142 3348 24679 0 0 00:06:40 3 ARISTA02T0
10.0.0.37 4 64003 143 3348 24679 0 0 00:06:40 4 ARISTA03T0
10.0.0.39 4 64004 142 3347 24679 0 0 00:06:40 3 ARISTA04T0
10.0.0.41 4 64005 143 3347 24679 0 0 00:06:39 4 ARISTA05T0
10.0.0.43 4 64006 142 3348 24679 0 0 00:06:40 3 ARISTA06T0
10.0.0.45 4 64007 142 3348 24679 0 0 00:06:40 3 ARISTA07T0
10.0.0.47 4 64008 142 3347 24679 0 0 00:06:40 3 ARISTA08T0
10.0.0.49 4 64009 142 3348 24679 0 0 00:06:40 3 ARISTA09T0
10.0.0.51 4 64010 142 3347 24679 0 0 00:06:40 3 ARISTA10T0
10.0.0.53 4 64011 136 3341 24679 0 0 00:06:31 3 ARISTA11T0
10.0.0.55 4 64012 136 3341 24679 0 0 00:06:31 3 ARISTA12T0
10.0.0.57 4 64013 136 3341 24679 0 0 00:06:31 3 ARISTA13T0
10.0.0.59 4 64014 136 3341 24679 0 0 00:06:32 3 ARISTA14T0
10.0.0.61 4 64015 135 3340 24679 0 0 00:06:28 3 ARISTA15T0
10.0.0.63 4 64016 142 3347 24679 0 0 00:06:39 3 ARISTA16T0
10.0.0.65 4 64017 141 3348 24679 0 0 00:06:40 1 ARISTA17T0
10.0.0.67 4 64018 135 3341 24679 0 0 00:06:31 1 ARISTA18T0
10.0.0.69 4 64019 135 3341 24679 0 0 00:06:31 1 ARISTA19T0
10.0.0.71 4 64020 135 3341 24679 0 0 00:06:32 1 ARISTA20T0
```

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Signed-off-by: zitingguo-ms <[email protected]>

platform/broadcom/sai.mk

@@ -1,6 +1,6 @@
-LIBSAIBCM_XGS_VERSION = 12.1.0.2
+LIBSAIBCM_XGS_VERSION = 12.3.0.3
 LIBSAIBCM_DNX_VERSION = 11.2.13.1-1
-LIBSAIBCM_XGS_BRANCH_NAME = SAI_12.1.0_GA
+LIBSAIBCM_XGS_BRANCH_NAME = SAI_12.3.0_GA
 LIBSAIBCM_DNX_BRANCH_NAME = SAI_11.2.0_GA
 LIBSAIBCM_XGS_URL_PREFIX = "https://sonicstorage.blob.core.windows.net/public/sai/sai-broadcom/$(LIBSAIBCM_XGS_BRANCH_NAME)/$(LIBSAIBCM_XGS_VERSION)/xgs"
 LIBSAIBCM_DNX_URL_PREFIX = "https://sonicstorage.blob.core.windows.net/public/sai/sai-broadcom/$(LIBSAIBCM_DNX_BRANCH_NAME)/$(LIBSAIBCM_DNX_VERSION)/dnx"