[L0 v2] Remove ur_shared_handle

as it's error prone to use - similarly to shared_ptr
we should not create multiple instances of shared_handle
from a single raw pointer.

Also, fix error in kernel.cpp: program handle was not
being retained, leading to segfaults.

Author: igchor

source/adapters/level_zero/v2/common.hpp

@@ -102,4 +102,5 @@ using ze_context_handle_t =
 using ze_command_list_handle_t =
     ze_handle_wrapper<::ze_command_list_handle_t, zeCommandListDestroy>;
 
+} // namespace raii
 } // namespace v2