Poll history - setup labs setting (#10039)

* add settings while under development

* very basic tests for roomsummarycard

* empty poll history dialog and option in room summary

* pollS history in settings

* use more user-centric selectors in roomsummarycard test

src/settings/Settings.tsx

@@ -382,6 +382,14 @@ export const SETTINGS: { [setting: string]: ISetting } = {
         description: _td("Defaults to room member list."),
         default: false,
     },
+    "feature_poll_history": {
+        isFeature: true,
+        labsGroup: LabGroup.Rooms,
+        supportedLevels: LEVELS_FEATURE,
+        displayName: _td("Polls history"),
+        description: _td("View a list of polls in a room. (Under active development)"),
+        default: false,
+    },
     "feature_jump_to_date": {
         // We purposely leave out `isFeature: true` so it doesn't show in Labs
         // by default. We will conditionally show it depending on whether we can