use React.Children.count for counting children

[vonovak]

Summary

just a minor change - uses the count api

Returns the total number of components in children, equal to the number of times that a callback passed to map or forEach would be invoked.

Changelog

not needed I think

Test Plan

tested locally

[pull-bot]

Messages

📖

📋 Verify Changelog Format - A changelog entry has the following format: [CATEGORY] [TYPE] - Message. CATEGORY may be: General iOS Android JavaScript Internal (for changes that do not need to be called out in the release notes) TYPE may be: Added, for new features. Changed, for changes in existing functionality. Deprecated, for soon-to-be removed features. Removed, for now removed features. Fixed, for any bug fixes. Security, in case of vulnerabilities. MESSAGE may answer "what and why" on a feature level. Use this to briefly tell React Native users about notable changes.

Generated by 🚫 dangerJS against a6b6140

[analysis-bot]

Platform	Engine	Arch	Size (bytes)	Diff
android	hermes	arm64-v8a	6,778,884	-18
android	hermes	armeabi-v7a	6,441,109	-33
android	hermes	x86	7,164,006	-12
android	hermes	x86_64	7,054,657	-26
android	jsc	arm64-v8a	8,947,379	13
android	jsc	armeabi-v7a	8,601,990	-25
android	jsc	x86	8,775,619	-8
android	jsc	x86_64	9,351,919	-1

Base commit: fd97e95

[analysis-bot]

Platform	Engine	Arch	Size (bytes)	Diff
ios	-	universal	10,721,520	9,911,952

Base commit: fd97e95

[facebook-github-bot]

@TheSavior is landing this pull request. If you are a Facebook employee, you can view this diff on Phabricator.

[react-native-bot]

This pull request was successfully merged by @vonovak in 92160f3.

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