feat: add triggerRef prop to dropdown

[mxschll]

Description

Introduces a new triggerRef prop to the Dropdown.

Related links, issue #, if available: n/a

How has this been tested?

Pipeline is green.

Review checklist

The following items are to be evaluated by the author(s) and the reviewer(s).

Correctness

• Changes include appropriate documentation updates.
• Changes are backward-compatible if not indicated, see CONTRIBUTING.md.
• Changes do not include unsupported browser features, see CONTRIBUTING.md.
• Changes were manually tested for accessibility, see accessibility guidelines.

Security

• If the code handles URLs: all URLs are validated through the checkSafeUrl function.

Testing

• Changes are covered with new/existing unit tests?
• Changes are covered with new/existing integration tests?

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 97.43%. Comparing base (80272d6) to head (13225a7).

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #4285   +/-   ##
=======================================
  Coverage   97.43%   97.43%           
=======================================
  Files         896      896           
  Lines       26298    26306    +8     
  Branches     9496     9501    +5     
=======================================
+ Hits        25623    25631    +8     
- Misses        632      669   +37     
+ Partials       43        6   -37     

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[mxschll]

Trigger can be any HTML element

[mxschll]

Might update this comment after API proposal for trigger ref.