Update new-shortcut-mapping flag expiration

Change-Id: I04618576c547cea0336ec387a61d015902eab5ed
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3141044


Commit-Queue: Jimmy Gong <jimmyxgong@chromium.org>
Commit-Queue: Zentaro Kavanagh <zentaro@chromium.org>
Auto-Submit: Jimmy Gong <jimmyxgong@chromium.org>
Reviewed-by: Zentaro Kavanagh <zentaro@chromium.org>
Cr-Commit-Position: refs/heads/main@{#918279}