message: Use `blt_convert_to_system_includes` macro instead of `blt_patch_target` for lua import
  Also removes some debug lines, per PR review.
diff: @@ -244,23 +244,8 @@ if (LUA_DIR)
  EXPORTABLE ON)
  endif()
  - blt_print_target_properties(TARGET lua)
  - blt_print_variables(NAME_REGEX lua IGNORE_CASE)
  -
  - # Mark includes as SYSTEM if target is not IMPORTED
  - # Includes for IMPORTED are already marked as system
  - # and calling it would generate a CMake error.
  - # TODO: This logic should be incorporated into blt_patch_target
  - get_target_property(_is_lua_imported lua IMPORTED)
  - if(NOT ${_is_lua_imported})
  - blt_patch_target(NAME lua TREAT_INCLUDES_AS_SYSTEM ON)
  - endif()
  -
  + blt_convert_to_system_includes(TARGET lua)
  blt_list_append(TO TPL_DEPS ELEMENTS lua)
  -
  - blt_print_target_properties(TARGET lua)
  - blt_print_variables(NAME_REGEX lua IGNORE_CASE)
  - blt_print_variables(VALUE_REGEX lua IGNORE_CASE)
  else()
  message(STATUS "LUA support is OFF")
  set(LUA_FOUND OFF CACHE BOOL "")
  