Prefer submitting a new approval over dismissing a stale review to clear merge gates

When a PR is blocked by an outdated CHANGES_REQUESTED review from the user (BYK) and the user is also the reviewer, the user consistently opts to clear the gate by approving the latest commit rather than dismissing the old review. This applies whenever a stale review causes mergeable_state=BLOCKED and the review threads are resolved. The assistant should first confirm with the user before modifying review state, then on user's decision, submit a fresh approving review on the current head commit via the API. Avoid dismissing reviews unless explicitly requested; the user's preference is to supersede the old review with a new one.