Enhance/#7598 - Add GA4 availableCustomDimensions module setting and relevant datastore infrastructure

[hussain-t]

Summary

Addresses issue:

• Add GA4 availableCustomDimensions module setting and relevant datastore infrastructure #7598

Relevant technical choices

PR Author Checklist

• My code is tested and passes existing unit tests.
• My code has an appropriate set of unit tests which all pass.
• My code is backward-compatible with WordPress 5.2 and PHP 5.6.
• My code follows the WordPress coding standards.
• My code has proper inline documentation.
• I have added a QA Brief on the issue linked above.
• I have signed the Contributor License Agreement (see https://cla.developers.google.com/).

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Code Reviewer Checklist

• Run the code.
• Ensure the acceptance criteria are satisfied.
• Reassess the implementation with the IB.
• Ensure no unrelated changes are included.
• Ensure CI checks pass.
• Check Storybook where applicable.
• Ensure there is a QA Brief.

Merge Reviewer Checklist

• Ensure the PR has the correct target branch.
• Double-check that the PR is okay to be merged.
• Ensure the corresponding issue has a ZenHub release assigned.
• Add a changelog message to the issue.

[github-actions]

Build files for 0be09ec have been deleted.

[eugene-manuilov]

Thanks, @hussain-t. This is a very solid start. Found some minor issues that we need to fix before merging this PR. Please, take a look at my comments.

[eugene-manuilov]

Nice job, @hussain-t. Approved!

[eugene-manuilov]

Actually, there are PHP issues in e2e tests that we need to fix to prevent them failing. @hussain-t, could you please take a look at it?

[hussain-t]

Actually, there are PHP issues in e2e tests that we need to fix to prevent them failing. @hussain-t, could you please take a look at it?

@eugene-manuilov, those aren't related to the changes involved in this PR. I've seen them failing in other PR as well. Let me re-check.

[eugene-manuilov]

Ok, thanks, @hussain-t. Looks like that is not relevant to these changes. Ok, approving this PR.