state->settings was malloc'd in lis2dw_monitor_face_setup() outside
the guard that only runs on first allocation of the face's context.
setup() is called again every time the watch wakes from deep sleep
(movement.c's app_setup() re-runs watch_faces[i].setup() for every
face on wake), so each wake cycle allocated a new settings array and
abandoned the previous pointer with no matching free.
Since NUM_SETTINGS is a compile-time constant, make settings a
fixed-size array embedded directly in lis2dw_monitor_state_t instead
of a separately malloc'd pointer, so it's allocated exactly once
along with the rest of the state and never leaks.