ref(wsgi): Delete custom _werkzeug and use new Werkzeug version

[mgaligniana]

Fixes: GH-3516

[codecov]

Codecov Report

❌ Patch coverage is 80.00000% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 84.91%. Comparing base (e012ff1) to head (47d563c).

Files with missing lines	Patch %	Lines
sentry_sdk/integrations/wsgi.py	80.00%	1 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #4708      +/-   ##
==========================================
+ Coverage   84.87%   84.91%   +0.04%     
==========================================
  Files         156      155       -1     
  Lines       16109    16090      -19     
  Branches     2740     2732       -8     
==========================================
- Hits        13672    13663       -9     
+ Misses       1650     1643       -7     
+ Partials      787      784       -3     

Files with missing lines	Coverage Δ
sentry_sdk/integrations/wsgi.py	94.85% <80.00%> (-1.25%)	⬇️

... and 2 files with indirect coverage changes