Remove Heroicons hex package

[stuartc]

Description

This PR removes Heroicons (the hex package) in favour of using our Tailwind system.

Validation steps

Check the application for missing icons.

Additional notes for the reviewer

This can't be merged until downstream applications that expect Heroicons to be installed as a transistive dependency either add Heroicons or conform with the <.icon name="hero-..." /> component.

Pre-submission checklist

• I have performed a self-review of my code.
• I have implemented and tested all related authorization policies. (e.g., :owner, :admin, :editor, :viewer)
• I have updated the changelog.

[codecov]

Codecov Report

Attention: Patch coverage is 68.96552% with 9 lines in your changes missing coverage. Please review.

Project coverage is 89.84%. Comparing base (fc29ed4) to head (a3ff899).
Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
lib/lightning_web/live/run_live/components.ex	52.94%	8 Missing ⚠️
lib/lightning_web/live/modal_portal.ex	0.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2487      +/-   ##
==========================================
+ Coverage   89.79%   89.84%   +0.04%     
==========================================
  Files         314      314              
  Lines       10842    10830      -12     
==========================================
- Hits         9736     9730       -6     
+ Misses       1106     1100       -6     

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