Speed up admin page when loading users

[elsaperelli]

Pull requests into Cypress require the following. Submitter and reviewer should ✅ when done. For items that are not-applicable, note it's not-applicable ("N/A") and ✅.

Summary

This PR speeds up the admin page by eager-loading users’ roles and assigned resources, then reusing that prepared @users list in the view instead of querying MongoDB again for each user.

Submitter:

• This pull request describes why these changes were made.
• Internal ticket for this PR:
• Internal ticket links to this PR
• Code diff has been done and been reviewed
• Tests are included and test edge cases
• Tests have been run locally and pass

Reviewer 1:

Name:

• Code is maintainable and reusable, reuses existing code and infrastructure where appropriate, and accomplishes the task’s purpose
• The tests appropriately test the new code, including edge cases
• You have tried to break the code

Reviewer 2:

Name:

• Code is maintainable and reusable, reuses existing code and infrastructure where appropriate, and accomplishes the task’s purpose
• The tests appropriately test the new code, including edge cases
• You have tried to break the code

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 91.59%. Comparing base (31efd48) to head (b067f33).
⚠️ Report is 1 commits behind head on master.

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #2075   +/-   ##
=======================================
  Coverage   91.59%   91.59%           
=======================================
  Files         159      159           
  Lines        7378     7379    +1     
=======================================
+ Hits         6758     6759    +1     
  Misses        620      620           

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