fix: make GRH=false more robust

[thofma]

No description provided.

[codecov]

Codecov Report

Attention: Patch coverage is 95.83333% with 2 lines in your changes missing coverage. Please review.

Project coverage is 75.60%. Comparing base (bd11391) to head (8867a71).
Report is 4 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1570      +/-   ##
==========================================
- Coverage   75.64%   75.60%   -0.05%     
==========================================
  Files         357      357              
  Lines      113521   113542      +21     
==========================================
- Hits        85872    85841      -31     
- Misses      27649    27701      +52     

Files	Coverage Δ
src/AlgAss/AlgQuat.jl	79.87% <100.00%> (ø)
src/AlgAssAbsOrd/PIP/bley_johnston.jl	68.46% <100.00%> (ø)
src/AlgAssAbsOrd/PIP/unit_group_generators.jl	57.62% <100.00%> (+0.48%)	⬆️
src/AlgAssAbsOrd/PicardGroup.jl	85.19% <100.00%> (ø)
src/AlgAssAbsOrd/UnitGroup.jl	58.03% <100.00%> (ø)
src/NumFieldOrd/NfOrd/Unit/Regulator.jl	100.00% <100.00%> (ø)
src/AlgAssAbsOrd/LocallyFreeClassGroup.jl	92.32% <66.66%> (ø)
src/NumFieldOrd/NfOrd/Clgp.jl	83.39% <93.75%> (+0.62%)	⬆️

... and 21 files with indirect coverage changes