Command Palette: Enqueue command-related assets for all admin pages

[wildworks]

This ticket tracks the backport of PHP files for the following Gutenberg update:

​Command Palette: Enqueue assets globally #71264

We're aiming to bring the Command Palette into all parts of the WordPress site, as described in the ​Roadmap to 6.9 post.

As a first step, just like the Gutenberg plugin, this ticket aims to enable the Command Palette on all admin pages by enqueuing command-related assets via the admin_enqueue_scripts hook.

Trac ticket: https://core.trac.wordpress.org/ticket/63845

Related Gutenberg PR: ​https://github.com/WordPress/gutenberg/pull/71264

[wildworks]

Note: The attached PR can't be committed until the latest npm packages are synced to the core. This is because the wp.coreCommands.initializeCommandPalette() method in the code doesn't exist in core yet. The attached PR will need to be committed after the package sync for Beta 1 is complete.

[wildworks]

Update:

The attached PR can't be committed until the latest npm packages are synced to the core. This is because the wp.coreCommands.initializeCommandPalette() method in the code doesn't exist in core yet.

I'm testing this PR again now that the package has been updated, and it appears that the styles are not being applied to the dashboard. I'll investigate the cause.

[wildworks]

Styles not applied to the Command Palette UI

[wildworks]

I'm testing this PR again now that the package has been updated, and it appears that the styles are not being applied to the dashboard. I'll investigate the cause.

Fixed.

[cbravobernal]

In 61022:

Command Palette: Enqueue command-related assets for all admin pages.

Removes the core command initialization and registration code from the edit-post and edit-site packages and enqueues command-related assets globally.

Props wildworks, rcorrales, shailu25, youknowriad.

Fixes #63845.

Committed in https://core.trac.wordpress.org/changeset/61022