Glass does not support translucent textures

The Bug

The glass block does not support the alpha channel.

Now that the engine supports translucent textures in stained glass, clear glass should do this as well. It currently hinders resource packs, and causes strange behavior in mipmapping since the alpha value adjacent pixels can't be averaged together correctly.

To Reproduce

1. Download and enable the resource pack: glass-transparency-test-1.18.1.zip
2. Put down a glass block.

Expected Behavior

It should look like blue stained glass, with the transparency.

Observed Behavior

It's solid blue.