Add settings toggle for instance-wide uncommitted warning

[isc-pbarton]

Resolves #936
Tested by toggling the setting in the UI, saving, confirming the setting was saved in the backend.

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 50.91%. Comparing base (c5e6557) to head (2cfebdb).

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #940   +/-   ##
=======================================
  Coverage   50.91%   50.91%           
=======================================
  Files          23       23           
  Lines        3131     3131           
=======================================
  Hits         1594     1594           
  Misses       1537     1537           

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[isc-dchui]

I believe you've tagged the wrong issue in the description, but otherwise looks good!