Fixes #45075
Fixes #57210

If an asset was included directly from the project root directory, then the same asset when copied to various output or ephemeral directories would also be picked up as an asset variant. This could cause assets to be recursively copied into asset/build/ephemeral directories, as each time it would run it would pick up all of the previous "variants".

The solution is to include project ephemeral directories, in addition to the build directory.