* Helix: make rgblight modes selectable.
No change in build result.
* edit the comment of helix/rev2/keymaps/default/keymap.c
* Helix led_test keymap: reduced the size.
* now helix led_test local rgblight.[ch] not use. remove.
* greatly simplify keyboards/helix/rev2/keymaps/led_test/keymap.c
Helix keymap 'led_test' use modified default/keymap.c