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/right_panel/PinnedMessagesCard.tsx

@@ -133,6 +133,7 @@ const PinnedMessagesCard: React.FC<IProps> = ({ room, onClose, permalinkCreator
                     if (event.isEncrypted()) {
                         await cli.decryptEventIfNeeded(event); // TODO await?
                     }
+                    await room.processPollEvents([event]);
 
                     if (event && PinningUtils.isPinnable(event)) {
                         // Inject sender information