Inserter: nested overflow on patterns tab #65837

Description

There’s an extra scrolling area appearing in the inserter on the patterns tab (probably the media tab too if it had enough content to overflow).

It seems to have come about after #64371 (tested by checking out the parent commit b7bf133 and noting the lack of the issue). It may be that it’s no fault of that PR’s changes and some detail of this use case is "doing it wrong".

Step-by-step reproduction instructions

1. Have a look at the patterns tab with a window short enough that there’s overflow

Screenshots, screen recording, code snippet

Environment info

No response

Please confirm that you have searched existing issues in the repo.

• Yes

Please confirm that you have tested with all plugins deactivated except Gutenberg.

• Yes