Navigation block link popover has a 0 in it after unlinking and relinking

[talldan]

Description

There's a 0 being shown in the nav block's link UI after a particular sequence of steps. I imagine this is accidentally being returned from a React component instead of null or undefined.

Step-by-step reproduction instructions

1. Add a nav block
2. Start empty
3. Add a link
4. Select a URL to a page or post
5. Once done, click the link icon on the toolbar
6. Click the 'unlink' button in the link popover
7. Click on the 'Add link' text
8. Observe the link popover shows with a 0 in the top left corner

Screenshots, screen recording, code snippet

Environment info

Tested on latest trunk at the time of writing.
Tested using Brave on Mac OS.

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

[Mamaduka]

If anyone is interested, this is the line that caused the bug:

gutenberg/packages/block-editor/src/components/link-control/index.js

Line 256 in 40ff1e5

const showTextControl = value?.url?.trim()?.length && hasTextControl;

You can find details about "why" this is happening in new React docs (see the "Gotcha" part).

[amustaque97]

I would love to take this forward and fix it.