fix: mitigate many unnecessary api calls in user management table

[keita-determined]

Description

WEB-1965

Test Plan

• Check if no initial user role api calls in user tab in user management table with RBAC enabled (see WEB-1965 for more details)
• Check if user information is correct in edit user modal and works as expected
• Check if user can be newly created in create user modal

Commentary (optional)

Checklist

• Changes have been manually QA'd
• User-facing API changes need the "User-facing API Change" label.
• Release notes should be added as a separate file under docs/release-notes/.
  See Release Note for details.
• Licenses should be included for new code which was copied and/or modified from any external code.

Ticket

[netlify]

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[codecov]

Codecov Report

Attention: 9 lines in your changes are missing coverage. Please review.

Comparison is base (3805ebd) 47.72% compared to head (45d7f8e) 42.73%.
Report is 4 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #8816      +/-   ##
==========================================
- Coverage   47.72%   42.73%   -4.99%     
==========================================
  Files        1049      732     -317     
  Lines      167293   128617   -38676     
  Branches     2243     2238       -5     
==========================================
- Hits        79846    54970   -24876     
+ Misses      87289    73489   -13800     
  Partials      158      158              

Flag	Coverage Δ
harness	?
web	42.52% <78.57%> (+<0.01%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files	Coverage Δ
webui/react/src/components/CreateUserModal.tsx	89.54% <100.00%> (+2.62%)	⬆️
webui/react/src/pages/Admin/UserManagement.tsx	83.27% <68.96%> (-0.96%)	⬇️

... and 317 files with indirect coverage changes

[gt2345]

LGTM