Regression: Some buttons don't show their tooltips any longer

[afercia]

Describe the bug

This seems to be a regression in the plugin, current version is 9.0.0.

Worth reminding that tooltips are important for accessibility because:

• icons don't have a universal meaning (different cultural backgrounds, cognitive impairments, etc,)
• tooltips are the only way to visually expose the name of icon-only controls to users of assistive technologies, more importantly to users of speech recognition software

To reproduce

• first: test without the Gutenberg plugin activated
• edit a post and select a Paragraph block
• the block toolbar appears
• hover (or tab to) all the toolbar buttons and observe they all display their tooltip
• activate the Gutenberg plugin
• repeat the steps above
• observe not all buttons display their tooltips

Here's some buttons that don't show tooltips any longer. This list doesn't pretend to be exhaustive, it's just to point to some clear examples and to highlight it doesn't happen only in the editor:

Paragraph block toolbar:

• Change block type or style
• Change text alignment
• More rich text controls
• More options

On the new Navigation page:

• More rich text controls
• More options

On Full Site Editing with a template part selected:

• Change block type or style
• Change alignment
• More options

Git bisect told me the offending commit is e703aee which is #24304.
Cc @tellthemachines

Expected behavior
All the icon-only buttons to display their tooltip.

Editor version (please complete the following information):

• WordPress version: 5.6 trunk
• Does the website has Gutenberg plugin installed, or is it using the block editor that comes by default? plugin
• If the Gutenberg plugin is installed, which version is it? 9.0.0