Command Palette: Don't include palate on Network Admin

[t-hamano]

Trac ticket: https://core.trac.wordpress.org/ticket/64125

In the network admin screen, commands primarily intended for site editors don't work, such as Go to : Styles and Go to: Templates.

These commands are registered in JS, namely Gutenberg. Ideally, we'd need to detect network admin status client-side and disable comments. As a temporary fix, disable the command palette itself in the network admin area to avoid 404 errors.

Testing Instructions

• Define LOCAL_MULTISITE=true in the .env file
• Run: npm run env:start, npm run env:install, and npm run dev
• Access to http://localhost:8889/wp-admin/network/
• Try to launch the Comand Palette and confirm that nothing happens

[github-actions]

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[github-actions]

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[t-hamano]

This issue may be better resolved on the client side rather than the server side, so I'm closing this PR for now. See: WordPress/gutenberg#72572