On nested Heading blocks, the "Change heading level" button loses padding when clicked

[ZebulanStanphill]

The issue

When you click the heading level button in a Heading block toolbar, some of its left spacing disappears for some reason. But this only happens when the Heading block is nested in another block.

(Ignore the mover placement in the screenshot; I took the picture on another branch, but I tested to make sure the bug was in master.)

I think this regressed due to changes in #20246. The cause appears to be due to a style rule being applied when this <span> is created upon clicking the button:

How to reproduce

1. Insert a Group block.
2. In that block, insert a Heading block.
3. Click the "Change heading level" button.
4. Notice how the padding on the left side of the button shrinks.

[ZebulanStanphill]

Something else I just noticed is that the "Change heading level" button label tooltip doesn't appear when the block is nested. Possibly related?

[ZebulanStanphill]

Reopening because this was accidentally closed instead of #22863. 😆

[ntsekouras]

Notice how the padding on the left side of the button shrinks.

Hey @ZebulanStanphill, it seems that this has been fixed and the button takes these styles, introduced in this PR #21252.

Can you please verify it's okay now?

[ZebulanStanphill]

@ntsekouras It was still broken when #21252 was merged (this issue wasn't even open yet back then), but something has changed since then and everything seems to be working now! 😄