Check mOwnedByTransform to avoid DELSA on SPI

The owned by transform flag prevents the removal
of an SPI from accidentally deleting an associated
SA in the kernel. That flag wasn't actually being
checked, so deleting an SPI would result in the
transform being removed.

The existing code already guarantees that the SA is
deleted when the transform is deleted

Bug: 73258845
Test: runtest frameworks-net
Change-Id: I4c26aea7af817a5d9e54da5db1cdf4f943bcae06