Add admin action to change organization handle

[jenshenny]

Currently, users are only able to create an organization based on a gem name they own. As more organizations onboard and get created, we need to be able to help them change their handle in admin if none of their gems match the name they want.

This PR adds an admin action to change the org handle.

[jenshenny]

The avo action passes an array to find_by_handle and expects a collection / array to be returned.

[codecov]

Codecov Report

❌ Patch coverage is 90.47619% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 97.24%. Comparing base (3abc053) to head (93409d8).
⚠️ Report is 10 commits behind head on master.

Files with missing lines	Patch %	Lines
app/avo/actions/change_organization_handle.rb	85.71%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #6218      +/-   ##
==========================================
- Coverage   97.25%   97.24%   -0.02%     
==========================================
  Files         477      478       +1     
  Lines        9847     9867      +20     
==========================================
+ Hits         9577     9595      +18     
- Misses        270      272       +2     

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