[ios][precompile] change to angled include in umbrella

[chrfalch]

Summary:

To make the later VFS overlays work, our React umbrella header needs to use angled import syntax instead of quoted".

This is so that the compiler will look up by module and not only by path.

Prev PR: https://github.com/facebook/react-native/pull/54839 Next PR: https://github.com/facebook/react-native/pull/54841

Changelog:

[IOS] [FIXED] - changed umbrella header template to use angled import syntax

Test Plan:

Run RNTester with prebuilds

[github-actions[bot]]

Job Summary for Gradle

Test All :: run_fantom_tests

Gradle Root Project	Requested Tasks	Gradle Version	Build Outcome	Build Scan®
react-native-github	:private:react-native-fantom:buildFantomTester	9.0.0	:x: