Customize: Ensure autosave revision is dismissed immediately after implicit...

Customize: Ensure autosave revision is dismissed immediately after implicit restoration notice dismissal as done with explicit notice dismissal.

Fixes issue where a drafted/scheduled changeset could inadvertently re-use the previous autosave revision in the preview while a user expects it to have been dismissed.

See #39896, [41597].
Fixes #42502 for trunk.

Built from https://develop.svn.wordpress.org/trunk@42144


git-svn-id: https://core.svn.wordpress.org/trunk@41975 1a063a9b-81f0-0310-95a4-ce76da25c4cd