Better checking for empty tools list

[antonpirker]

Fixes #4646

[codecov]

Codecov Report

❌ Patch coverage is 83.33333% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 80.73%. Comparing base (70e2b59) to head (8d89584).
⚠️ Report is 1 commits behind head on master.
✅ All tests successful. No failed tests found.

Files with missing lines	Patch %	Lines
sentry_sdk/integrations/openai.py	83.33%	0 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #4647      +/-   ##
==========================================
- Coverage   80.75%   80.73%   -0.02%     
==========================================
  Files         156      156              
  Lines       16632    16636       +4     
  Branches     2831     2831              
==========================================
  Hits        13431    13431              
- Misses       2312     2313       +1     
- Partials      889      892       +3     

Files with missing lines	Coverage Δ
sentry_sdk/integrations/openai.py	84.41% <83.33%> (+0.16%)	⬆️

... and 2 files with indirect coverage changes