[Android] Add onUserLeaveHint support to ReactActivityDelegate #43488

[behenate]

Summary:

This PR adds onUserLeaveHint support into the ReactActivityDelegate. It allows modules to receive an event every time user moves the app into the background. This is slightly different than onPause - it's called only when the user intentionally moves the app into the background, e.g. when receiving a call onPause should be called but onUserLeaveHint shouldn't.

This feature is especially useful for libraries implementing features like Picture in Picture (PiP), where using onUserLeaveHint is the recommended way of auto-entering PiP for android < 12.

This is a re-submission of #42741 and #43488 without problematic asserts, which were unnecessary (onUserLeaveHint is not critical to the lifecycle of the app), but were causing problems in some apps.

Changelog:

[ANDROID] [ADDED] - Added onUserLeaveHint support into ReactActivityDelegate

Test Plan:

Tested in the rn-tester app - callbacks are correctly called on both old and new architecture.

[behenate]

@cortinico Do you think we want to keep the log(method); in ReactHostImpl? I have mixed feelings about it, but methods like onHostPause and onHostResume have the log.

[facebook-github-bot]

@cortinico has imported this pull request. If you are a Meta employee, you can view this diff on Phabricator.

[analysis-bot]

Platform	Engine	Arch	Size (bytes)	Diff
android	hermes	arm64-v8a	18,073,874	-47,920
android	hermes	armeabi-v7a	n/a	--
android	hermes	x86	n/a	--
android	hermes	x86_64	n/a	--
android	jsc	arm64-v8a	21,440,618	-46,543
android	jsc	armeabi-v7a	n/a	--
android	jsc	x86	n/a	--
android	jsc	x86_64	n/a	--

Base commit: ce4d8f2
Branch: main

[facebook-github-bot]

@cortinico merged this pull request in 6450d08.