Update poll create placeholder text, fix test flake

Co-authored-by: yash-signal <yash@signal.org>

_locales/en/messages.json

@@ -1527,7 +1527,7 @@
     "description": "Label for the poll question input field"
   },
   "icu:PollCreateModal__questionPlaceholder": {
-    "messageformat": "What should we order for lunch?",
+    "messageformat": "Ask a question",
     "description": "Placeholder text for the poll question input field"
   },
   "icu:PollCreateModal__optionsLabel": {

ts/test-electron/state/ducks/username_test.preload.ts

@@ -122,7 +122,7 @@ describe('electron/state/ducks/username', () => {
         delay: 1000,
       })(dispatch, () => emptyState, null);
 
-      await clock.runToLastAsync();
+      await clock.tickAsync(1000);
       assert.strictEqual(clock.now, 1000);
 
       sinon.assert.calledOnce(dispatch);