Image block shows toolbar button to "Add text over image" even when core/cover block is nor registered

[fabiankaegy]

Description

The Core Image Block recently added an option to "Add text over image" which under the hood transforms the Image block to a Cover Block. This button still gets rendered in the Blocks Toolbar in cases where the Cover Block is not registered.

Instances where this can happen is when a site uses white / blacklisting.

Expected behaviour

When the Core Cover block is not registered the button should not show anymore.

Actual behaviour

When the Core Cover block is not registered the button does snow but doesn't do anything.

WordPress information

• WordPress version: "5.7.2"
• Gutenberg version: "Not installed"
• Are all plugins except Gutenberg deactivated? "Yes"
• Are you using a default theme (e.g. Twenty Twenty-One)? "Yes"

[Mamaduka]

I pushed the PR to fix issue #32666.