response: Implement ignored parameters with MutableJsonResponse class.

Creates `MutableJsonResponse` as a subclass of Django's `HttpResponse`
that we can modify for ignored parameters in the response content.

Updates responses to include `ignored_parameters_unsupported` in
the response data through `has_request_variables`. Creates unit
test for this implementation in `test_decorators.py`.

The `method` parameter processed in `rest_dispatch` is not in the
`REQ` framework, so for any tests that pass that parameter, assert
for the ignored parameter with a comment.

Updates OpenAPI documentation for `ignored_parameters_unsupported`
being returned in the JSON success response for all endpoints.
Adds detailed documentation in the error handling article, and
links to that page in relevant locations throughout the API docs.

For the majority of endpoints, the documentation does not include
the array in any examples of return values, and instead links to
the error handling page. The exceptions are the three endpoints
that had previously supported this return value. The changes note
and example for these endpoints is also used in the error
handling page.

zerver/views/streams.py

@@ -1051,16 +1051,4 @@ def update_subscription_properties_backend(
             user_profile, sub, stream, property, value, acting_user=user_profile
         )
 
-    # TODO: Do this more generally, see update_realm_user_settings_defaults.realm.py
-    from zerver.lib.request import RequestNotes
-
-    request_notes = RequestNotes.get_notes(request)
-    for req_var in request.POST:
-        if req_var not in request_notes.processed_parameters:
-            request_notes.ignored_parameters.add(req_var)
-
-    result: Dict[str, Any] = {}
-    if len(request_notes.ignored_parameters) > 0:
-        result["ignored_parameters_unsupported"] = list(request_notes.ignored_parameters)
-
-    return json_success(request, data=result)
+    return json_success(request)