The asset handle type is supposed to be replaced by the asset
representation type. It is designed for the asset system as opposed to
the file browser backend. With d421ebac5e, d04cd3f3e6 and f6a6b27ac1, it
can now do everything that is needed in Python to be a replacement.
591a1ae323 removed all usages of these members in the asset handle and
the file entry wrapped by the asset handle. All this should now be
accessed via the `bpy.types.AssetRepresentation` type instead, which is
available everywhere the `AssetHandle` type was available before.
Part of #102877 and #108806.
d973cc7992