[iOS] Rename SigninRecallPromo into UpgradeSigninPromo

=> crrev.com/c/3122179
 * crrev.com/i/4086755
 * crrev.com/c/3122093

Change-Id: I87f772d5a401f45ce60b6317dd6369519395ce34
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3122179


Auto-Submit: Jérôme <jlebel@chromium.org>
Reviewed-by: Sylvain Defresne <sdefresne@chromium.org>
Reviewed-by: Nohemi Fernandez <fernandex@chromium.org>
Commit-Queue: Sylvain Defresne <sdefresne@chromium.org>
Commit-Queue: Jérôme <jlebel@chromium.org>
Cr-Commit-Position: refs/heads/main@{#915894}