chore: RCTConvert - allocate array with capacity

[vonovak]

Summary

this is a trivial change that allocates the NSMutableArray with the correct capacity before it is filled

Changelog

[Internal] [Changed] - RCTConvertVecToArray - allocate array with capacity

Test Plan

tested locally: the code builds and runs as expected

[analysis-bot]

Platform	Engine	Arch	Size (bytes)	Diff
android	hermes	arm64-v8a	7,103,533	+0
android	hermes	armeabi-v7a	6,471,857	+0
android	hermes	x86	7,521,168	+0
android	hermes	x86_64	7,380,054	+0
android	jsc	arm64-v8a	8,968,359	+0
android	jsc	armeabi-v7a	7,699,467	+0
android	jsc	x86	9,030,658	+0
android	jsc	x86_64	9,508,690	+0

Base commit: ca1ae5c
Branch: main

[pull-bot]

PR build artifact for e91fe36 is ready.
To use, download tarball from "Artifacts" tab in this CircleCI job then run yarn add <path to tarball> in your React Native project.

[iBotPeaches]

tested locally: the code builds and runs as expected

Doesn't look like its building :) - double check your syntax. I believe you have an extra [ in there.

[vonovak]

lol, since it was just a one-liner I didn't bother to create a branch and push from it locally, and just copy-pasted in the GH ui... well, now it's fixed. Thanks 👍

[analysis-bot]

Platform	Engine	Arch	Size (bytes)	Diff
ios	-	universal	n/a	--

Base commit: ca1ae5c
Branch: main

[pull-bot]

PR build artifact for 5ff140a is ready.
To use, download tarball from "Artifacts" tab in this CircleCI job then run yarn add <path to tarball> in your React Native project.

[facebook-github-bot]

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

[react-native-bot]

This pull request was successfully merged by @vonovak in e325c95.

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