Fix wsgi invalid request uri (#4551)

* Fix WSGI invalid request URI handling

* Simplifying the test request_uri

* Adding suggestion

* Fixing falcon tests

* Adding explicit query_string for full_request_uri

* Adding changelog entry

* Updating test with hardcoded value

* Add changelog fragment

* Update test

Add PATH_INFO to the environment for CONNECT request.

* Apply suggestions from code review

Co-authored-by: Riccardo Magliocchetti <riccardo.magliocchetti@gmail.com>

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Co-authored-by: Emídio Neto <9735060+emdneto@users.noreply.github.com>
Co-authored-by: Riccardo Magliocchetti <riccardo.magliocchetti@gmail.com>