Fix icon size on Sensei blocks appender

[renatho]

Resolves #7308

Proposed Changes

• I fixed it originally with a Gutenberg PR: Fix DropdownMenu svg icon size WordPress/gutenberg#56450
• But while it's not merged and to be fixed in the versions where it's broken, I'm sending this PR with a workaround. Basically, it just adds the missing width and height to the svg in the DropdownMenu component.

Testing Instructions

1. Create a new course.
2. Add a Course Outline block.
3. Click on "+".
4. Check that the icons are displayed correctly.

Pre-Merge Checklist

• PR title and description contain sufficient detail and accurately describe the changes
• Acceptance criteria is met
• Decisions are publicly documented
• Adheres to coding standards (PHP, JavaScript, CSS, HTML)
• All strings are translatable (without concatenation, handles plurals)
• Follows our naming conventions (P6rkRX-4oA-p2)
• Hooks (p6rkRX-1uS-p2) and functions are documented
• New UIs are responsive and use a mobile-first approach
• New UIs match the designs
• Different user privileges (admin, teacher, subscriber) are tested as appropriate
• Code is tested on the minimum supported PHP and WordPress versions
• User interface changes have been tested on the latest versions of Chrome, Firefox and Safari
• "Needs Documentation" label is added if this change requires updates to documentation
• Known issues are created as new GitHub issues

[codecov]

Codecov Report

Merging #7316 (592cd74) into trunk (5389d5b) will not change coverage.
Report is 1 commits behind head on trunk.
The diff coverage is n/a.

Additional details and impacted files

@@            Coverage Diff            @@
##              trunk    #7316   +/-   ##
=========================================
  Coverage     50.81%   50.81%           
  Complexity    11060    11060           
=========================================
  Files           611      611           
  Lines         46727    46727           
  Branches        404      404           
=========================================
  Hits          23744    23744           
  Misses        22656    22656           
  Partials        327      327           

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[m1r0]

Looks good. 👍