Disable auto sync PRs with target branch

[iamdharmesh]

Description of the Change

PR removes explicitly enabled auto sync PR feature to stop PR syncing.

Reason for disabling this: (until we find a way to handle this better way, want to keep this disabled)

• It keeps sending notifications from PRs for every sync.
• GH action not getting triggered for the sync commit, which makes the unknown status of checks on the latest PR commit.

How to test the Change

Changelog Entry

Changed - Disabled auto sync pull requests with target branch.

Credits

Props @iamdharmesh

Checklist:

• I agree to follow this project's Code of Conduct.
• I have updated the documentation accordingly.
• I have added tests to cover my change.
• All new and existing tests pass.