Template parts: use "Change design" drop down instead of Design panel

[ramonjd]

What problem does this address?

To make designs available always (in Write mode especially), let's relocate the sidebar “design” panel for template parts to the block toolbar, similar to the Query block.

Follow up to: #66993

Current location of design patterns for template parts

The "Change design" button for the query block

What is your proposed solution?

Look for a way to make this control "generic", for example, as part of a hook in the block editor package.

Then it could be extracted from the Query block code, moved to a central location, and applied to both the query and template part blocks.

See this comment:

#66993 (comment)

[richtabor]

The "Change design" button for the query block

@ramon Another follow up, for the query block though, would be to use the same styles for the popover as "Change design" does from zoom out. The current popover is pretty rough as-is.

[ramonjd]

Thanks for the feedback @richtabor I'll take a look when I next get a chance.

[ramonjd]

use the same styles for the popover as "Change design" does from zoom out

• Query block: style the change design drop down to match the zoomed out section toolbar #67553