wip deps use my forked flutter_local_notifications, with collision fix

(The alternative workaround would be to pass distinct notif "id" integers.
These could be a hash of the tag... but if it's merely hashCode,
there'd be risk of collisions.)

I feel like the right answer here is that the plugin should be a much
thinner layer, much closer to just exposing the underlying API.
(Also it can use Pigeon to simplify the transport boilerplate.)
Then our Dart code can express what we want.

lib/notifications.dart

@@ -203,10 +203,6 @@ class NotificationDisplayManager {
         color: kZulipBrandColor,
         icon: 'zulip_notification', // TODO vary for debug
         // TODO(#128) inbox-style
-
-        // TODO plugin sets PendingIntent.FLAG_UPDATE_CURRENT; is that OK?
-        // TODO plugin's setContentIntent doesn't set our Intent flags; is that OK?
-        // TODO all notifs lead to convo of latest notif, because plugin's setContentIntent doesn't avoid dupe URLs
       )));
   }
 

pubspec.lock

@@ -425,9 +425,11 @@ packages:
   flutter_local_notifications:
     dependency: "direct main"
     description:
-      path: "../local-notifications/flutter_local_notifications"
-      relative: true
-    source: path
+      path: flutter_local_notifications
+      ref: "5a0239b36"
+      resolved-ref: "5a0239b36c1f4e6a89d079bfbf96bb533a8179d9"
+      url: "https://github.com/gnprice/flutter_local_notifications"
+    source: git
     version: "15.1.0+1"
   flutter_local_notifications_linux:
     dependency: transitive

pubspec.yaml

@@ -64,7 +64,11 @@ dependencies:
   firebase_core: ^2.14.0
   flutter_local_notifications_platform_interface: ^7.0.0+1
   flutter_local_notifications:
-    path: ../local-notifications/flutter_local_notifications
+    # path: ../local-notifications/flutter_local_notifications
+    git:
+      url: https://github.com/gnprice/flutter_local_notifications
+      ref: 5a0239b36
+      path: flutter_local_notifications/
 
 dev_dependencies:
   flutter_test: