Fix default hip debug flags

@helloworld922 observed that in debug hip configs, we were getting `"-g -O"` (i.e. without an optimization level) and found that this was being set by `CMAKE_HIP_FLAGS_DEBUG`.

@white238 found that this was a bug in CMake that was addressed in https://gitlab.kitware.com/cmake/cmake/-/merge_requests/10572
(see https://gitlab.kitware.com/cmake/cmake/-/issues/26823 for more info).

It looks like this bugfix will be available in cmake@4.1.0.
We should add a bugfix for this to blt when the cmake version is below cmake@4.1.0

Start by locating BLT's handling of CMAKE_HIP_FLAGS_DEBUG and any CMake-version checks. Compare behavior for CMake versions below 4.1.0, then verify that debug HIP flags include an optimization level on affected versions and run the relevant build or testing checks.

Written by the indexing model from the issue text.