Upgrade mypy to 0.711, drop no longer needed workarounds (#24998)

https://mypy-lang.blogspot.com/2019/06/mypy-0711-released.html

homeassistant/config_entries.py

@@ -257,8 +257,7 @@ class ConfigEntry:
                           self.title, self.domain)
             return False
         # Handler may be a partial
-        # type ignore: https://github.com/python/typeshed/pull/3077
-        while isinstance(handler, functools.partial):  # type: ignore
+        while isinstance(handler, functools.partial):
             handler = handler.func
 
         if self.version == handler.VERSION: