GLTF Mesh Import Materials Handling: Quick Fix for Metallic/Roughness and Emissive

I understand that the GLTF Mesh Uploader materials import handling is in a temporary state and more is planned to match the incoming GLTF material properties.

Its currently setting the base colour correctly whether image or simple colour based, and it seems to be adding the numerical values for metallic factor and roughness, and colour tint for emissive. This is helpful and lets the user adjust the materials even at this early stage.

But the metallic/roughness and emission properties do not seem to be enabled unless a texture is added to those to let the set values apply. Blank allows he numeric properties to apply as a basis for use straight away.

Temporary suggestion: Fill in the metallic/roughness (for any values at all) and emission (if not full black #000000) with the default "Blank" so that these properties are immediately available to the user.

Observed in Second Life Project Gltf-mesh-import 7.1.14.15307986327