Protected packages: Add missing feature category to controller tests

What does this MR do and why?

The option feature_category is missing in the changed tests. This causes (unnecessary) warnings when executing the tests. This MR fixes this by setting the feature category to :package_registry as this is also set in the respective controller files.

🛠 with ❤ at Siemens

MR acceptance checklist

Please evaluate this MR against the MR acceptance checklist. It helps you analyze changes to reduce risks in quality, performance, reliability, security, and maintainability.

MR Checklist (@gerardo-navarro)

• Changelog entry added, if necessary
• Documentation created/updated via this MR
• Documentation reviewed by technical writer or follow-up review issue created
• Tests added for this feature/bug
• Tested in all supported browsers
• Conforms to the code review guidelines
• Conforms to the merge request performance guidelines
• Conforms to the style guides
• Conforms to the javascript style guides
• Conforms to the database guides

Screenshots or screen recordings

No frontend . Only changes in test

How to set up and validate locally

1. Run the changed tests and make sure that warning regarding the missing feature_category is not shown

bundle rspec spec/controllers/projects/packages/packages_controller_spec.rb spec/controllers/projects/packages/infrastructure_registry_controller_spec.rb

Related to #413641