Remove extra MultiDictProxy wrapper from BaseRequest.query (#…

…9098)

(cherry picked from commit 94685fb)

aiohttp/web_request.py

@@ -486,7 +486,7 @@ def raw_path(self) -> str:
     @reify
     def query(self) -> "MultiMapping[str]":
         """A multidict with all the variables in the query string."""
-        return MultiDictProxy(self._rel_url.query)
+        return self._rel_url.query
 
     @reify
     def query_string(self) -> str: