use Poll model with relations API in poll rendering (#9877)

* wip

* remove dupe

* use poll model relations in all cases

* update mpollbody tests to use poll instance

* update poll fetching login in pinned messages card

* add pinned polls to room polls state

* add spinner while relations are still loading

* handle no poll in end poll dialog

* strict errors

* strict fix

* more strict fix

src/components/views/context_menus/MessageContextMenu.tsx

@@ -195,7 +195,7 @@ export default class MessageContextMenu extends React.Component<IProps, IState>
         return (
             M_POLL_START.matches(mxEvent.getType()) &&
             this.state.canRedact &&
-            !isPollEnded(mxEvent, MatrixClientPeg.get(), this.props.getRelationsForEvent)
+            !isPollEnded(mxEvent, MatrixClientPeg.get())
         );
     }