Fix autoscrollToTopThreshold on iOS old arch

[janicduplessis]

Summary:

Currently autoscrollToTopThreshold does not work correctly, it will scroll to top even when the scroll position is past the autoscrollToTopThreshold value.

The value of x/y is taken before we adjust the scroll position so we do not need to subtract the delta.

Note that this was already fixed when I ported this code to fabric, so this fix is only needed in the old arch code.

Changelog:

[IOS] [FIXED] - Fix autoscrollToTopThreshold on iOS old arch

Test Plan:

In RNTester example, threshold is set to 10, so it should not scroll to top if we are further than 10px from the top of the list.

Before:

https://github.com/facebook/react-native/assets/2677334/13723787-1bc4-4263-9bcb-91ddf7454de3

After:

https://github.com/facebook/react-native/assets/2677334/a8cfdaac-59fc-40de-970a-ff992366e25f

[analysis-bot]

Platform	Engine	Arch	Size (bytes)	Diff
android	hermes	arm64-v8a	9,001,856	+4
android	hermes	armeabi-v7a	8,255,912	+4
android	hermes	x86	9,510,995	+3
android	hermes	x86_64	9,356,876	+4
android	jsc	arm64-v8a	9,614,918	+6
android	jsc	armeabi-v7a	8,741,555	+1
android	jsc	x86	9,701,870	+5
android	jsc	x86_64	9,948,431	+3

Base commit: 1706066533f457ec79213f2813908b5624c220f6 Branch: main

[janicduplessis]

@cipolleschi could you have a look at this?

[facebook-github-bot]

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

[github-actions[bot]]

This pull request was successfully merged by @janicduplessis in 9666814750198574170a26e21a47b028f8060ffe.

^{When will my fix make it into a release? | Upcoming Releases}

[facebook-github-bot]

@cipolleschi merged this pull request in facebook/react-native@9666814750198574170a26e21a47b028f8060ffe.