Replace AppMigration11 by a dismissal when entering the login flow

AppMigration11 was run once, in the first release containing it, whatever
the state of the MultiAccount feature flag. Users installing the app
while the feature flag was disabled were considered as new users and
would never see the announcement once the feature flag got enabled.

The multi-account announcement is now pending by default (NeverShown),
and is marked as shown when the user enters the login flow while the
feature is enabled, either for the first time or to add another account.
Users who were already logged in before the feature became available
will see the announcement.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

features/announcement/impl/src/main/kotlin/io/element/android/features/announcement/impl/DefaultAnnouncementService.kt

@@ -51,7 +51,9 @@ class DefaultAnnouncementService(
                 if (newNotificationSoundStatus == AnnouncementStatus.Show) {
                     add(Announcement.NewNotificationSound)
                 }
-                if (multiAccountStatus == AnnouncementStatus.Show) {
+                // The multi-account announcement is pending until it is dismissed. Users who were already
+                // logged in when the feature became available still have the default NeverShown status.
+                if (multiAccountStatus != AnnouncementStatus.Shown) {
                     add(Announcement.MultiAccount)
                 }
             }

features/announcement/impl/src/main/kotlin/io/element/android/features/announcement/impl/store/DefaultAnnouncementStore.kt

@@ -40,7 +40,8 @@ class DefaultAnnouncementStore(
         // NOT replay on first launch.
         // - Fullscreen.Space is disabled
         // - NewNotificationSound is opted in by AppMigration08
-        // - MultiAccount is NeverShown by default, AppMigration11 sets it to Show or Shown.
+        // - MultiAccount is NeverShown by default, which means pending. It is set to Shown when the user enters
+        //   the login flow while the feature is enabled (see NotLoggedInFlowNode), or dismisses the announcement.
         val defaultStatus = when (announcement) {
             Announcement.Fullscreen.Space -> AnnouncementStatus.Shown
             Announcement.NewNotificationSound -> AnnouncementStatus.Shown

features/announcement/impl/src/test/kotlin/io/element/android/features/announcement/impl/DefaultAnnouncementServiceTest.kt

@@ -74,10 +74,12 @@ class DefaultAnnouncementServiceTest {
             announcementStore = announcementStore,
         )
         sut.announcementsToShowFlow().test {
-            assertThat(awaitItem()).isEmpty()
+            // MultiAccount is pending by default
+            assertThat(awaitItem()).containsExactly(Announcement.MultiAccount)
             announcementStore.setAnnouncementStatus(Announcement.NewNotificationSound, AnnouncementStatus.Show)
-            assertThat(awaitItem()).containsExactly(Announcement.NewNotificationSound)
+            assertThat(awaitItem()).containsExactly(Announcement.NewNotificationSound, Announcement.MultiAccount)
             announcementStore.setAnnouncementStatus(Announcement.MultiAccount, AnnouncementStatus.Show)
+            // Still pending
             assertThat(awaitItem()).containsExactly(Announcement.NewNotificationSound, Announcement.MultiAccount)
             announcementStore.setAnnouncementStatus(Announcement.NewNotificationSound, AnnouncementStatus.Shown)
             assertThat(awaitItem()).containsExactly(Announcement.MultiAccount)