[OpenMP] Ignore implicit casts on assertion for `use_device_ptr`

There was an assertion triggering when invoking a captured member whose
initializer was in a blase class. This patch fixes it by allowing the
assertion on implicit casts to the base class rather than only the base
class itself.

Fixes https://github.com/llvm/llvm-project/issues/61027

Reviewed By: tianshilei1992

Differential Revision: https://reviews.llvm.org/D144873