Method to override feature flag

- Replaced where it's used in GridSizeMigrationUtilTest.kt

bug: 268094298
test: manually/presubmit and GridSizeMigrationUtilTest photo: https://screenshot.googleplex.com/7cLtFSbBvxnYAFM
Change-Id: Id8e688b95b91b1b6a4962a4e092505cbb79603f7
3 files changed