WIP: Migrate dashboard dropdowns to 'new dropdown'

What does this MR do?

Preparation for #214582 (closed). As part of the effort to "star" or select a dashboard as a favorite we should display more information in each dropdown.

This MR migrates dashboard dropdowns to the new dropdown design and layout.

This change helps by migrating to the new dropdown that supports checked items and icons.

Introduces a consistency UX debt ☝

• By adding the new dropdown, the header appearance becomes slightly inconsistent by keeping buttons on the right that are not yet compliant with the new design.
  • This is mitigated by having the refresh button updated, so buttons that look different are in different corners of the header.

Screenshots

before	after

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

Closes #214582 (closed)