E2E test plugin blocks not loading in the Customize Widgets editor.

[talldan]

Description

#31406 seems to fix loading blocks from plugins in the customize widget editor.

But for some reason plugin blocks that are used for e2e tests aren't loading (#31406 (comment)).

This might indicate a similar problem will occur with some plugins.

When observing the block registration, I can see that several different instances of the core/blocks store are being registered (possibly due to #8981).

In the customizer editor, the plugin block is being registered after core blocks, while for the standalone editor the plugin block is being registered before.

Step-by-step reproduction instructions

1. In a local wp-env environment open localhost:9999/wp-admin
2. Enable the Customize Widgets experiment
3. Enable a test plugin that adds a block, like 'Gutenberg Test Custom Grouping Block'
4. Open Appearance > Customize > Widgets
5. Open the block library using the '+' button

Expected behaviour

The 'Alternative Group Block' is available

Actual behaviour

The 'Alternative Group Block' isn't available

[noisysocks]

I'm having trouble testing this. For some reason the widgets block editor doesn't load at all for me in the Customizer when browsing to localhost:8889. (It's fine in localhost:8888.)

[ndiego]

@talldan and @noisysocks this issue came up in our weekly Editor Bug Scrub and just wanted to check in and see if this was still an issue?

[ndiego]

Hi all, this issue was reviewed again during this week's Editor Bug Scrub. A few testers were not able to reproduce, and given that this issue has not seen any activity in quite a long time, we have decided to close it. If anyone is able to reproduce, feel free to reopen.