When a post type is passed to `get_block_templates()` in the query, return only the templates that match that post type.
Fixes an issue where:
* when a block template provided by a theme has been edited by the user
* and that template has specific defined `postTypes`
* but after editing, the template was available for all post types.
Follow-up to [52062].
Props aljullu, bernhard-reiter, hellofromTonya.
Fixes#55881.
git-svn-id: https://develop.svn.wordpress.org/trunk@54184 602fd350-edb4-49c9-b593-d223f7449a82
