Fix error on running texture modifiers for text decals

GameData/ConformalDecals/Plugins/ConformalDecals.dll

@@ -1,3 +1,3 @@
 version https://git-lfs.github.com/spec/v1
-oid sha256:598ebc36f53198687a2e77dc8947c70c7b883a5e91342b52c012938c61b89382
+oid sha256:5fe350d8ceec1f3336d7610d27dc5726e854922a709465e58ba50b74ac738f16
 size 81408

Source/ConformalDecals/MaterialProperties/MaterialTextureProperty.cs

@@ -67,8 +67,7 @@ namespace ConformalDecals.MaterialProperties {
         public override void Modify(Material material) {
             if (material == null) throw new ArgumentNullException(nameof(material));
             if (_texture == null) {
-                _texture = Texture2D.whiteTexture;
-                throw new NullReferenceException("texture is null, but should not be");
+                _texture = isNormal ? DecalConfig.BlankNormal : Texture2D.whiteTexture;
             }
 
             material.SetTexture(_propertyID, _texture);