fix: respect timeout setting in grpc method calls

[federicobond]

No description provided.

[codecov]

Codecov Report

Attention: Patch coverage is 83.33333% with 1 lines in your changes are missing coverage. Please review.

Project coverage is 92.02%. Comparing base (d8e10c7) to head (f7285f0).
Report is 13 commits behind head on main.

Files	Patch %	Lines
...src/openfeature/contrib/provider/flagd/provider.py	83.33%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #60      +/-   ##
==========================================
+ Coverage   90.55%   92.02%   +1.46%     
==========================================
  Files           8        8              
  Lines         180      188       +8     
==========================================
+ Hits          163      173      +10     
+ Misses         17       15       -2     

Flag	Coverage Δ
unittests	92.02% <83.33%> (+1.46%)	⬆️

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