Re-name "Delete" button to "Archive" on Design Tab

What does this MR do?

Continuing on from @gvso's work in !34586 (closed):

This MR changes the delete button for an archive button. As mentioned at #220964 (closed), currently it's scary to click the "Delete" button for one or more designs, because it sounds serious.

This MR only makes the necessary change in the design_management/ application (design_management_legacy is ignored)

A few additional css changes have been made to maintain better consistency in spacing of elements.

screenshots

Before	After

Modal

Toolbar loading bug fix

Before	After
bug	fix

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry
• Documentation (if required)
• Code review guidelines
• Merge request performance guidelines
• Style guides
• Database guides
• Separation of EE specific content

Availability and Testing

• Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.
• Tested in all supported browsers
• Informed Infrastructure department of a default or new setting change, if applicable per definition of done

Security

If this MR contains changes to processing or storing of credentials or tokens, authorization and authentication methods and other items described in the security review guidelines:

• Label as security and @ mention @gitlab-com/gl-security/appsec
• The MR includes necessary changes to maintain consistency between UI, API, email, or other methods
• Security reports checked/validated by a reviewer from the AppSec team