Remove unused property

Fixes #7108

Author: keveleigh

Assets/MixedRealityToolkit/Inspectors/Profiles/MixedRealityInputSystemProfileInspector.cs

@@ -19,7 +19,6 @@ public class MixedRealityInputSystemProfileInspector : BaseDataProviderServiceIn
 
         private static bool showDataProviders = false;
         private const string ShowInputSystem_DataProviders_PreferenceKey = "ShowInputSystem_DataProviders_PreferenceKey";
-        private SerializedProperty dataProviderConfigurations;
 
         private SerializedProperty focusProviderType;
         private SerializedProperty focusQueryBufferSize;