fix: Messages being encrypted for too many devices

lib/src/client.dart

@@ -1579,13 +1579,13 @@ sort order of ${prevState.sortOrder}. This should never happen...''');
   /// you can safely make this Client instance null.
   Future<void> dispose({bool closeDatabase = false}) async {
     _disposed = true;
-    encryption?.dispose();
-    encryption = null;
     try {
       await _currentTransaction;
     } catch (_) {
       // No-OP
     }
+    encryption?.dispose();
+    encryption = null;
     try {
       if (closeDatabase) await database?.close();
     } catch (error, stacktrace) {

lib/src/room.dart

@@ -1620,7 +1620,8 @@ class Room {
     var deviceKeys = <DeviceKeys>[];
     var users = await requestParticipants();
     for (final user in users) {
-      if (client.userDeviceKeys.containsKey(user.id)) {
+      if ([Membership.invite, Membership.join].contains(user.membership) &&
+          client.userDeviceKeys.containsKey(user.id)) {
         for (var deviceKeyEntry
             in client.userDeviceKeys[user.id].deviceKeys.values) {
           deviceKeys.add(deviceKeyEntry);

test/user_test.dart

@@ -133,7 +133,7 @@ void main() {
       expect(user1.canChangePowerLevel, false);
     });
     test('dispose client', () async {
-      await client.dispose();
+      await client.dispose(closeDatabase: true);
     });
   });
 }