Update SDK submodules to v2026.12-build.sisdk-2026.12-720 on release_2.10-1.6.1 (#1022)

Update SDK submodules to v2026.12-build.sisdk-2026.12-720

Co-authored-by: chirag-silabs <100861685+chirag-silabs@users.noreply.github.com>

Author: silabs-matter-ci-bot[bot]

.gitmodules

@@ -5,11 +5,11 @@
 [submodule "third_party/simplicity_sdk"]
 	path = third_party/simplicity_sdk
 	url = https://github.com/SiliconLabsSoftware/sisdk-prerelease.git
-	tag = v2026.12-build.sisdk-2026.12-664
+	tag = v2026.12-build.sisdk-2026.12-720
 [submodule "third_party/wifi_sdk"]
 	path = third_party/wifi_sdk
 	url = https://github.com/SiliconLabsSoftware/wiseconnect-prerelease.git
-	tag = v2026.12-build.sisdk-2026.12-664
+	tag = v2026.12-build.sisdk-2026.12-720
 [submodule "third_party/aws_ota_sdk/ota-for-aws-iot-embedded-sdk"]
 	path = third_party/aws_ota_sdk/ota-for-aws-iot-embedded-sdk
 	url = https://github.com/aws/ota-for-aws-iot-embedded-sdk.git