Drop responses from test requirements (home-assistant#65793)

Author: frenck

requirements_test.txt

@@ -27,7 +27,6 @@ pytest-timeout==2.1.0
 pytest-xdist==2.4.0
 pytest==6.2.5
 requests_mock==1.9.2
-responses==0.12.0
 respx==0.19.0
 stdlib-list==0.7.0
 tqdm==4.49.0