[sx1278] Removed a bunch of old TODOs

src/shared/radio/SX1278/SX1278Frontends.h

src/tests/radio/sx1278/lora/test-sx1278-bidir.cpp

src/tests/radio/sx1278/lora/test-sx1278-mavlink.cpp

src/tests/radio/sx1278/lora/test-sx1278-simple.cpp

src/tests/radio/sx1278/test-sx1278-bench-gui.cpp