Collapse enableResourceTimingAPI flag (#54511)

Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/54511

Simplify flagging of Network related features by dropping `enableResourceTimingAPI`.

This feature is stable (along with the rest of the Web Perf APIs), but this event type remains gated behind `enableNetworkEventReporting` (already enabled in `0.83-stable`). This preserves an opt-out ability for remaining unintegrated apps/platforms in fbsource.

Changelog: [Internal]

Reviewed By: rubennorte

Differential Revision: D86862905

fbshipit-source-id: 22ebe59486fb3d241c8beba30bb714dcc04a48ab