Admin: remove dead code

[bpandola]

Recent request parsing work has obviated the need for this specialized method.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 93.02%. Comparing base (107674b) to head (1139379).
⚠️ Report is 1 commits behind head on master.

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #9423   +/-   ##
=======================================
  Coverage   93.02%   93.02%           
=======================================
  Files        1292     1292           
  Lines      116110   116104    -6     
=======================================
- Hits       108008   108004    -4     
+ Misses       8102     8100    -2     

Flag	Coverage Δ
servertests	28.85% <0.00%> (+<0.01%)	⬆️
unittests	92.99% <100.00%> (+<0.01%)	⬆️

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