Remove sync issues workflow

[JamieMagee]

I don't believe the team uses this workflow anymore, and the underlying PAT expired a long time ago.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 89.6%. Comparing base (b6bac81) to head (1206ee6).
Report is 2 commits behind head on main.

Additional details and impacted files

@@          Coverage Diff          @@
##            main   #1399   +/-   ##
=====================================
  Coverage   89.6%   89.6%           
=====================================
  Files        401     401           
  Lines      31811   31811           
  Branches    1966    1966           
=====================================
+ Hits       28528   28529    +1     
  Misses      2863    2863           
+ Partials     420     419    -1     

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