notif: Prefix stream names with #

Fixes: #572

Author: rajveermalviya

lib/notifications/display.dart

@@ -94,9 +94,9 @@ class NotificationDisplayManager {
     final zulipLocalizations = GlobalLocalizations.zulipLocalizations;
     final title = switch (data.recipient) {
       FcmMessageStreamRecipient(:var streamName?, :var topic) =>
-        '$streamName > $topic',
+        '#$streamName > $topic',
       FcmMessageStreamRecipient(:var topic) =>
-        '(unknown stream) > $topic', // TODO get stream name from data
+        '#(unknown stream) > $topic', // TODO get stream name from data
       FcmMessageDmRecipient(:var allRecipientIds) when allRecipientIds.length > 2 =>
         zulipLocalizations.notifGroupDmConversationLabel(
           data.senderFullName, allRecipientIds.length - 2), // TODO use others' names, from data

test/notifications/display_test.dart

@@ -179,7 +179,7 @@ void main() {
       final stream = eg.stream();
       final message = eg.streamMessage(stream: stream);
       await checkNotifications(async, messageFcmMessage(message, streamName: stream.name),
-        expectedTitle: '${stream.name} > ${message.subject}',
+        expectedTitle: '#${stream.name} > ${message.subject}',
         expectedTagComponent: 'stream:${message.streamId}:${message.subject}');
     }));
 
@@ -188,7 +188,7 @@ void main() {
       final stream = eg.stream();
       final message = eg.streamMessage(stream: stream);
       await checkNotifications(async, messageFcmMessage(message, streamName: null),
-        expectedTitle: '(unknown stream) > ${message.subject}',
+        expectedTitle: '#(unknown stream) > ${message.subject}',
         expectedTagComponent: 'stream:${message.streamId}:${message.subject}');
     }));