fix(tracing): End http.client span on timeout

[Zylphrex]

If the http request times out, the http client span never gets finished. So make sure to finish it no matter what.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 83.15%. Comparing base (4c1367b) to head (60bed50).
Report is 9 commits behind head on master.

✅ All tests successful. No failed tests found.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #3723      +/-   ##
==========================================
- Coverage   84.28%   83.15%   -1.13%     
==========================================
  Files         133      133              
  Lines       14257    14476     +219     
  Branches     2405     2471      +66     
==========================================
+ Hits        12016    12037      +21     
- Misses       1490     1689     +199     
+ Partials      751      750       -1     

Files with missing lines	Coverage Δ
sentry_sdk/integrations/stdlib.py	99.20% <100.00%> (+<0.01%)	⬆️

... and 4 files with indirect coverage changes