Add waiting for the WS event

Author: sierpinskid

Assets/Plugins/StreamChat/Tests/StatefulClient/ChannelsTests.cs

@@ -330,7 +330,8 @@ await WaitWhileFalseAsync(
 
             await channel.UpdatePartialAsync(unsetFields: new string[] { "owned_dogs", "breakfast" });
 
-            //StreamTodo: this can potentially be non deterministic because we rely on WS event being received before call ends
+            await WaitWhileTrueAsync(
+                () => new[] { "owned_dogs", "breakfast" }.All(channel.CustomData.ContainsKey));
 
             Assert.IsFalse(channel.CustomData.ContainsKey("owned_dogs"));
             Assert.IsFalse(channel.CustomData.ContainsKey("breakfast"));