Remove usage of node for finding RN in gradle

[louiszawadzki]

What does this PR do?

Remove usage of node for finding RN in gradle.
The previous solution was triggering an error that was hard to understand when node could not be found: #575

For context, this change was originally introduced when migrating to RN 0.71 to keep retro-compatibility for earlier RN versions.

Additional Notes

I believe the proposed solution is the current best practice to get the path to node modules in gradle, I've seen it used in big community packages:

• react-native-webview
• react-native-reanimated

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