Material fails to compile when virtual texture is connected to opacity mask only through Make/Break Material Attributes

If we connect a virtual texture to the opacity mask output of a material the material will fail to compile. Currently this is expected because allowing it could cause problems such as:

• No virtual texture feedback in the shadow pass causing incorrectly cached shadows.
• No virtual texture feedback from masked pixels could cause virtual texture not to reach a good mip level.

If we connect only a regular texture we don't expect a problem.

However if the opacity mask uses a regular texture connected via MakeMaterialAttributes and BreakMaterialAttributes nodes and any virtual texture is connected to other properties in the MakeMaterialAttibutes then we still see a compile error.

It seems that the compilation validation logic is checking all texture samples connected to MakeMaterialAttributes instead of just the ones connected through the OpacityMask pin.

In a project where Virtual Textures are enabled, create a material like below.
[Link Removed]

Note that the texture connected to the BaseColor pin is a virtual texture, but the one connected to the OpacityMask pin is a regular texture.
Observe the material compilation error: "Sampling a virtual texture is currently not supported when connected to the Opacity Mask material attribute."
The expected behavior is for the material to compile.