Disallow import of non-deprecated name
The GlSkeletonLoading component was deprecated in favour of
GlSkeletonLoader as part of
&4301 (closed).
This makes sure that only the GlDeprecateSkeletonLoading import name
can be used, to remove any ambiguity about whether or not it's
deprecated.
Part of #357001 (closed).
Edited by Mark Florian