refactor(codegen): add getLiteralValue in parser

[Zwem]

Summary:

[Codegen 130] This PR add a getLiteralValue function to the Parser interface, which returns the literal value of an union represented, given an option. as requested on #34872

Changelog:

[INTERNAL] [ADDED] - Add getLiteralValue function to codegen Parser

Test Plan:

Run yarn jest react-native-codegen and ensure CI is green

[analysis-bot]

Platform	Engine	Arch	Size (bytes)	Diff
android	hermes	arm64-v8a	8,883,356	+2
android	hermes	armeabi-v7a	7,934,153	+0
android	hermes	x86	9,280,422	-1
android	hermes	x86_64	9,183,545	+1
android	jsc	arm64-v8a	9,473,065	+2
android	jsc	armeabi-v7a	8,416,419	+1
android	jsc	x86	9,455,816	+2
android	jsc	x86_64	9,772,024	+1

Base commit: e37e530
Branch: main

[Zwem]

@cipolleschi @rshest PR is ready for review but needs re run. circleci: test_windows (failed with 500 error)

[facebook-github-bot]

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

[github-actions]

This pull request was successfully merged by @Zwem in 6d5be26.

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