Remove TODO about informational responses (#3319)

Today it's not possible with HTTP/1.1 (see psf/requests#713) and even
python-hyper does not handle this case. This will be handled in
#3336.

src/urllib3/http2.py

@@ -130,12 +130,7 @@ def getresponse(  # type: ignore[override]
                 if received_data := self.sock.recv(65535):
                     events = h2_conn.receive_data(received_data)
                     for event in events:
-                        if isinstance(
-                            event, h2.events.InformationalResponseReceived
-                        ):  # Defensive:
-                            continue  # TODO: Does the stdlib do anything with these responses?
-
-                        elif isinstance(event, h2.events.ResponseReceived):
+                        if isinstance(event, h2.events.ResponseReceived):
                             headers = HTTPHeaderDict()
                             for header, value in event.headers:
                                 if header == b":status":