Fix text shadow on TextInput on Android when backgroundColor is set

[j-piasecki]

Summary:

When setting a shadow on a Text inside a TextInput, the shadow was rendered with artifacts when backgroundColor was set on the TextInput.

This is caused by how attributed strings are constructed on the new architecture - all text attributes from the text input (including background color) are propagated onto the string. Then, it's converted to a Spannable on Android side, which includes ReactBackgroundColorSpan being set on the entire text when it doesn't have a background color set explicitly. Then Android tries to render the shadow not only for the text but also for the background rect which results in the artifacts.

This PR prevents background color from the TextInput from being propagated onto the attributed string, so the ReactBackgroundColorSpan is only applied when a text fragment has its background set explicitly.

Changelog:

[ANDROID] [FIXED] - Fixed text shadow rendering with artifacts when backgroundColor was set on the TextInput

Test Plan:

Checked relevant examples on RNTester

Old arch	New arch (before)	New arch (after)

[cortinico]

/rebase

[analysis-bot]

Platform	Engine	Arch	Size (bytes)	Diff
android	hermes	arm64-v8a	21,300,844	+16,705
android	hermes	armeabi-v7a	n/a	--
android	hermes	x86	n/a	--
android	hermes	x86_64	n/a	--
android	jsc	arm64-v8a	24,497,590	+16,425
android	jsc	armeabi-v7a	n/a	--
android	jsc	x86	n/a	--
android	jsc	x86_64	n/a	--

Base commit: 12b64b7
Branch: main

[facebook-github-bot]

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

[facebook-github-bot]

@cortinico merged this pull request in 8371629.

[github-actions]

This pull request was successfully merged by @j-piasecki in 8371629.

^{When will my fix make it into a release? | How to file a pick request?}