Support for creator/owner power level (#30525)

* Support for creator/owner power level

This just shows them as 'Owner' in the list.

* Add test for owner level

src/components/views/settings/tabs/room/RolesRoomSettingsTab.tsx

@@ -348,10 +348,7 @@ export default class RolesRoomSettingsTab extends React.Component<IProps, RolesR
             powerLevelDescriptors.users_default.defaultValue,
         );
 
-        let currentUserLevel = userLevels[client.getUserId()!];
-        if (currentUserLevel === undefined) {
-            currentUserLevel = defaultUserLevel;
-        }
+        const currentUserLevel = room.getMember(client.getSafeUserId())?.powerLevel ?? defaultUserLevel;
 
         this.populateDefaultPlEvents(
             eventsLevels,