Update project to build on Gradle 7.0.2 (#32073)

Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/32073

This Diff bumps the version of Gradle used to build the project to
7.0.2. Ideally we could bump to 7.2.x directly, but I'll do one minor version
at a time to exclude potential build problems.

This diff is addressing all the extra build warnings that got raised by the new version.

Changelog:
[Android][Changed] - Bumped Gradle project version to 7.0.2

Reviewed By: ShikaSD

Differential Revision: D30486612

fbshipit-source-id: 70e0f7d18e547013ca7b1d12f8dd64a633df5870