light test: add EXTRA_ARGS processing on light tests

this way the light tests are filterable with the following formula:
```make light-check EXTRA_ARGS="-k test_unset_empties"```

Signed-off-by: shifter <[email protected]>
Signed-off-by: Hofi <[email protected]>

Author: bshifter

tests/light/CMakeLists.txt

@@ -3,7 +3,7 @@ add_custom_target(light-self-check
    DEPENDS BuildPyVirtualEnv)
 
 add_custom_target(light-check
-   COMMAND ${PYTHON_VENV_EXECUTABLE} -m pytest ${PROJECT_SOURCE_DIR}/tests/light/functional_tests --installdir=${CMAKE_INSTALL_PREFIX} --showlocals --verbosity=3
+   COMMAND ${PYTHON_VENV_EXECUTABLE} -m pytest ${PROJECT_SOURCE_DIR}/tests/light/functional_tests --installdir=${CMAKE_INSTALL_PREFIX} --showlocals --verbosity=3 $$EXTRA_ARGS
    DEPENDS BuildPyVirtualEnv)
 
 add_custom_target(light-linters