[NOJIRA] [FIX] Session Replay build issues

[sbarrio]

What does this PR do?

This PR does two things:

• Refactors the session-replay podspec file to properly align with newer versions of React Native, removing Folly flags and restructuring install_modules_dependencies. This solves build issues and potential hangups during the process.
• Closes the chokidar watcher after bundle_build_done so the Node process is able to exit, avoiding potential hangups that will hold up the build process.

Additional Notes

Tested on an specific Expo 54.0.33 RN 0.81.5 test app.

Review checklist (to be filled by reviewers)

• Feature or bugfix MUST have appropriate tests
• Make sure you discussed the feature or bugfix with the maintaining team in an Issue
• Make sure each commit and the PR mention the Issue number (cf the CONTRIBUTING doc)
• If this PR is auto-generated, please make sure also to manually update the code related to the change

[Copilot]

Pull request overview

This PR targets Session Replay build stability for newer React Native versions by updating the iOS podspec configuration and ensuring the Metro-side asset watcher doesn’t keep the Node process alive after bundling.

Changes:

• Refactors the Session Replay podspec to remove Folly compiler flags and restructure how new-architecture dependencies/xcconfig are applied.
• Updates the Metro asset bundler to close the chokidar watcher after bundle completion to allow CI/release Node processes to exit.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 3 comments.

File	Description
packages/react-native-session-replay/src/metro/index.ts	Switches from a boolean “watching” guard to a stored watcher instance and closes it after certain Metro reporter events.
packages/react-native-session-replay/DatadogSDKReactNativeSessionReplay.podspec	Removes Folly flags and reorganizes install_modules_dependencies + xcconfig application around RCT_NEW_ARCH_ENABLED.

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[marco-saia-datadog]

I am running E2E tests (#108489552) to check for regressions before approving.

[cdn34dd]

As previously discussed, I would keep the old flags for previous versions, and only change them for the newer ones.

[sbarrio]

The thing is, we don't set this flags in any other podspec on the SDK. I also ran the E2E suite against this PR and it builds properly even on RN 0.65.

[marco-saia-datadog]

E2E tests are all green, I believe it's safe to merge.