Site Editor > Patterns: Empty template parts use the text "Empty pattern" in the placeholder

[carolinan]

Description

This is a small inconsistency, but if you create a custom template part that is empty, and then go to
Admin > Editor > Patterns > Template parts, then the preview to the right of the menu is empty but has the wrong text. It says pattern instead of template part.

Step-by-step reproduction instructions

Create a custom empty template part through the interface
Go to Admin > Editor > Patterns > Template parts. Select the area used for the part, for example, General.
Confirm that the preview is empty, which is correct, but that the text says "Empty pattern"

Screenshots, screen recording, code snippet

Environment info

No response

Please confirm that you have searched existing issues in the repo.

Yes

Please confirm that you have tested with all plugins deactivated except Gutenberg.

Yes

[jordesign]

I can confirm this in testing - it also refers to the pattern within the Template Part details screen.

[aaronrobertshaw]

Thanks for the confirmation @jordesign and flagging the additional label.

A fix for both is up in #53842. A quick sanity check and reapproval might be good given I've updated that PR to tweak the extra label since the original green light.