fix: Sending of the to_device key

With the switch to hive a regression of sending the to_device key was
introduced: When popping elements .deleteAt(), so deleting at the index,
was used, instead of .delete(), so deleting of the key. As the new events
pushed onto the queue used hives auto increment key, a .delete() is
appropriate here.

lib/src/database/hive_database.dart

@@ -208,7 +208,7 @@ class FamedlySdkHiveDatabase extends DatabaseApi {
 
   @override
   Future<void> deleteFromToDeviceQueue(int clientId, int id) async {
-    await _toDeviceQueueBox.deleteAt(id);
+    await _toDeviceQueueBox.delete(id);
     return;
   }
 

test/client_test.dart

@@ -523,6 +523,59 @@ void main() {
           bunnyContent);
       await client.dispose(closeDatabase: true);
     });
+    test('send to_device queue multiple', () async {
+      // we test:
+      // send fox --> fail
+      // send raccoon --> fail
+      // send bunny --> all sent
+      final client = await getClient();
+      FakeMatrixApi.failToDevice = true;
+      final foxContent = {
+        '@fox:example.org': {
+          '*': {
+            'fox': 'hole',
+          },
+        },
+      };
+      final raccoonContent = {
+        '@fox:example.org': {
+          '*': {
+            'raccoon': 'mask',
+          },
+        },
+      };
+      final bunnyContent = {
+        '@fox:example.org': {
+          '*': {
+            'bunny': 'burrow',
+          },
+        },
+      };
+      await client
+          .sendToDevice('foxies', 'floof_txnid', foxContent)
+          .catchError((e) => null); // ignore the error
+      await client
+          .sendToDevice('raccoon', 'raccoon_txnid', raccoonContent)
+          .catchError((e) => null);
+      FakeMatrixApi.failToDevice = false;
+      FakeMatrixApi.calledEndpoints.clear();
+      await client.sendToDevice('bunny', 'bunny_txnid', bunnyContent);
+      expect(
+          json.decode(FakeMatrixApi
+                  .calledEndpoints['/client/r0/sendToDevice/foxies/floof_txnid']
+              [0])['messages'],
+          foxContent);
+      expect(
+          json.decode(FakeMatrixApi.calledEndpoints[
+              '/client/r0/sendToDevice/raccoon/raccoon_txnid'][0])['messages'],
+          raccoonContent);
+      expect(
+          json.decode(FakeMatrixApi
+                  .calledEndpoints['/client/r0/sendToDevice/bunny/bunny_txnid']
+              [0])['messages'],
+          bunnyContent);
+      await client.dispose(closeDatabase: true);
+    });
     test('Test the fake store api', () async {
       final database = await getDatabase(null);
       final client1 = Client(