[backport v2.8-Next2] Add rule for UIPlugin resources in default ResourceSet

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This is an automated request to port PR #508 by @mallardduck

Original PR body:

This PR seeks to resolve issue #483

Test Steps

• In a local cluster with the Kamaji UI extension installed, manually edited the default ResourceSet to include the new rule for UIPlugins.
• Took a backup (B1)
• See if B1 correctly includes the Kamaji UIPlugin
• Create a new cluster and restore the backup as detailed here
• Once restored, enable extensions in the new cluster and reload the page. Check if Kamaji UI remains correctly installed.