This improves the logic within `excerpt_remove_blocks()` to better handle `innerBlocks`. This prevents an empty excerpt from being returned when `core/columns`, `core/column`, and `core/group` blocks are present. This issue has been surfaced in the Query Loop block, where excerpts can be set to display. Props aristath. Fixes #53604. Built from https://develop.svn.wordpress.org/trunk@51348 git-svn-id: http://core.svn.wordpress.org/trunk@50957 1a063a9b-81f0-0310-95a4-ce76da25c4cd