[AppContainer] Add back legacy rootTag childContex

[nadiia]

Summary

Reverting the legacy rootTag childContext in AppContainer for 0.65 release. It will be deprecated and removed in the following release.

Changelog

[General] [Changed] - [AppContainer] Add back legacy rootTag childContex

Test Plan

CI test run

[pull-bot]

	Warnings
⚠️	❔ Base Branch - The base branch for this PR is something other than master. Are you sure you want to merge these changes into a stable release? If you are interested in backporting updates to an older release, the suggested approach is to land those changes on master first and then cherry-pick the commits into the branch for that release. The Releases Guide has more information.

Generated by 🚫 dangerJS against 325aa5f

[analysis-bot]

Platform	Engine	Arch	Size (bytes)	Diff
ios	-	universal	n/a	--

Base commit: 1e39d8b

[analysis-bot]

Platform	Engine	Arch	Size (bytes)	Diff
android	hermes	arm64-v8a	8,863,295	-123,367
android	hermes	armeabi-v7a	8,385,755	-108,154
android	hermes	x86	9,320,969	-117,974
android	hermes	x86_64	9,264,719	-115,992
android	jsc	arm64-v8a	10,592,385	-12,758
android	jsc	armeabi-v7a	10,097,940	-7,480
android	jsc	x86	10,611,563	-12,587
android	jsc	x86_64	11,195,564	-12,261

Base commit: 1e39d8b