Simplify face blend application for custom FaceWindowPanes

Check file path rather than specifying that the blendset is custom face.

COM3D2.MeidoPhotoStudio.Plugin/MeidoPhotoStudio/GUI/Panes/FaceWindowPanes/MaidFaceBlendPane.cs

@@ -62,7 +62,7 @@ namespace COM3D2.MeidoPhotoStudio.Plugin
             faceBlendDropdown.SelectionChange += (s, a) =>
             {
                 if (!faceListEnabled || updating) return;
-                this.meidoManager.ActiveMeido.SetFaceBlendSet(SelectedFace, facePresetMode);
+                this.meidoManager.ActiveMeido.SetFaceBlendSet(SelectedFace);
             };
 
             facePrevButton = new Button("<");

COM3D2.MeidoPhotoStudio.Plugin/MeidoPhotoStudio/Meido/Meido.cs

@@ -424,9 +424,9 @@ namespace COM3D2.MeidoPhotoStudio.Plugin
             return faceData;
         }
 
-        public void SetFaceBlendSet(string blendSet, bool custom = false)
+        public void SetFaceBlendSet(string blendSet)
         {
-            if (custom)
+            if (blendSet.StartsWith(Constants.customFacePath))
             {
                 string blendSetFileName = Path.GetFileNameWithoutExtension(blendSet);
                 try