Admin bar: don't enqueue obsolete Core CSS overrides for Default scheme

[fushar]

Fixes:

• Masterbar: the background color for Default scheme is wrong wp-calypso#94650

Proposed changes:

This PR ensures that we're not enqueuing any obsolete CSS overrides for the Default scheme. After pfsHM7-1kz-p2, such overrides are not required anymore. However, #39371 accidentally re-added them because it re-registers the fresh scheme using our CSS file (which contains the override).

This PR fixes that by just removing the override inclusion from that CSS file.

Other information:

• Have you written new tests for your changes, if applicable?
• Have you checked the E2E test CI results, and verified that your changes do not break them?
• Have you tested your changes on WordPress.com, if applicable (if so, you'll see a generated comment below with a script to run)?

Jetpack product discussion

Does this pull request change what data or activity we track or use?

Testing instructions:

1. Prepare a NEW Woa site.
   • It is important so that you won't get the cached colors.css.
   • Don't forget to add define( 'JETPACK_MU_WPCOM_LOAD_VIA_BETA_PLUGIN', true ); in wp-config.php
2. Patch this to Jetpack Beta Tester (WP.com Features)
3. Go to Users -> Profile and change the color scheme to Default.
4. Verify that the admin bar background color is #c3c4c7.
5. Verify that no colors are broken.

[github-actions]

Are you an Automattician? Please test your changes on all WordPress.com environments to help mitigate accidental explosions.

• To test on WoA, go to the Plugins menu on a WordPress.com Simple site. Click on the "Upload" button and follow the upgrade flow to be able to upload, install, and activate the Jetpack Beta plugin. Once the plugin is active, go to Jetpack > Jetpack Beta, select your plugin, and enable the fix/fresh-masterbar branch.

  • For jetpack-mu-wpcom changes, also add define( 'JETPACK_MU_WPCOM_LOAD_VIA_BETA_PLUGIN', true ); to your wp-config.php file.

• To test on Simple, run the following command on your sandbox:

  bin/jetpack-downloader test jetpack fix/fresh-masterbar
  

  bin/jetpack-downloader test jetpack-mu-wpcom-plugin fix/fresh-masterbar
  

Interested in more tips and information?

• In your local development environment, use the jetpack rsync command to sync your changes to a WoA dev blog.
• Read more about our development workflow here: PCYsg-eg0-p2
• Figure out when your changes will be shipped to customers here: PCYsg-eg5-p2

[github-actions]

Thank you for your PR!

When contributing to Jetpack, we have a few suggestions that can help us test and review your patch:

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This comment will be updated as you work on your PR and make changes. If you think that some of those checks are not needed for your PR, please explain why you think so. Thanks for cooperation 🤖

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