Bug 1932668 - Fix page content assertions in verifyCalendarFormInteractionsTest r=aaronmt DONTBUILD

Following up from https://bugzilla.mozilla.org/show_bug.cgi?id=1932366 I've fixed the way we assert the date selected on the calendar form to pass regardless of the Fission pref state.
Try run https://treeherder.mozilla.org/jobs?repo=try&revision=c77c2cdeda1612c1e010035caad9a48195ad51e5&selectedTaskRun=SNbMopPoTO2FVhoxne0m6g.0

Differential Revision: https://phabricator.services.mozilla.com/D229806

mobile/android/fenix/app/src/androidTest/java/org/mozilla/fenix/ui/robots/BrowserRobot.kt

@@ -725,9 +725,8 @@ class BrowserRobot {
 
     fun verifyNoDateIsSelected() {
         val currentDate = LocalDate.now()
-        assertUIObjectExists(
-            itemContainingText("Selected date is: $currentDate"),
-            exists = false,
+        assertTrue(
+            itemContainingText("Selected date is: $currentDate").waitUntilGone(waitingTime)
         )
     }