[Radio] Adjusted SX1278 tests with the correct library path

src/tests/drivers/sx1278/test-sx1278-bench.cpp

src/tests/drivers/sx1278/test-sx1278-bidir.cpp

src/tests/drivers/sx1278/test-sx1278-core.h

src/tests/drivers/sx1278/test-sx1278-mavlink.cpp

src/tests/drivers/sx1278/test-sx1278-serial.cpp