Fix/remove empty space from inserter

[n2erjo00]

What?

This PR is removing unnecessary empty space(s) in the Inserter panel.

Why?

Closes #56802

In the inserter panel the goal is to remove space between content area and search results

How?

The InserterPanel component takes a title property. After checking Gutenberg codebase revealed that property is either plain string or VisuallyHidden component. Added logic now checks whether title property is specifically VisuallyHidden component and use proper classes after that

Testing Instructions

1. Open a post or page.
2. Open Inserter panel
3. Observe the labels before block listing
4. Search for "Social" and observe there is no empty space before the list(s).
5. Search for "Social with" this returns pattern list and again observe no empty space before the list and hover effect still works on the pattern list items

This one hard to describe. Please also check the linked issue there are some really good screenshots (one picture versus million words)

Testing Instructions for Keyboard

Screenshots or screencast

[richtabor]

Hey @n2erjo00, stumbled upon this while exploring #61051. If that idea goes through, we won't need to check for visibility as those labels would be persistent throughout.

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[richtabor]

I think we should close this; but I could use a hand with the Inserter optimizations visualized as a part of #61051.

[n2erjo00]

@richtabor Makes sense, let's close this one.

I can checkout the linked issue later this week. Is there anything specific you'd need help with?

[richtabor]

I think the search results for patterns and blocks from the block directory could use cleaning up. The results in general are difficult to parse as-is.