Use workflow activation limiter on index toggle

[jyeshe]

Description

This PR fixes the workflow usage limiting when using the a toggle on the workflows index/list.

It also propagates the limit error change/assigns so that the create button is disabled without a page refresh.

Closes #2778

Validation steps

1. On the billing app using this branch, go to the workflows list of a free subscription
2. Deactivate the existing workflow(s)
3. Create a new one and activate it
4. Try to activate another one on the workflows list

AI Usage

Please disclose how you've used AI in this work (it's cool, we just want to know!):

• Code generation (copilot but not intellisense)
• Learning or fact checking
• Strategy / design
• Optimisation / refactoring
• Translation / spellchecking / doc gen
• Other
• I have not used AI

You can read more details in our Responsible AI Policy

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.
• I have ticked a box in "AI usage" in this PR

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 91.25%. Comparing base (c9cad42) to head (914c3e1).
Report is 5 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2777      +/-   ##
==========================================
- Coverage   91.25%   91.25%   -0.01%     
==========================================
  Files         335      335              
  Lines       11933    11932       -1     
==========================================
- Hits        10890    10889       -1     
  Misses       1043     1043              

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[stuartc]

Please update the CHANGLELOG

[elias-ba]

Nice one @jyeshe 👏🏽, thanks