Fix GMock library target usage
Fixes the following errors:
CMake Error at tests/unit-tests/CMakeLists.txt:43 (add_dependencies):
The dependency target "GMock" of target "lsc_unit_tests" does not exist.
CMake Error at tests/integration-tests/CMakeLists.txt:57 (add_dependencies):
The dependency target "GMock" of target "lsc_integration_tests" does not
exist.
Edited by Luca Weiss