Correct deferred concepts with NTTP placeholder constraints

Seemingly we never tested this, but the constraint on a NTTP was being
swtiched to the 'instantiated' version, but constraints need to be
relative to the 'top level', so this was causing us to not be able to
check the constraint on final use.

This patch corrects the issue by making the constraint created with the
un-instantiated version in the case of dependent constraint attachment.

Fixes: #61777