synthio: fix crash on synthesizer.press((float,))

Author: jepler

shared-module/synthio/Synthesizer.c

@@ -110,11 +110,12 @@ void common_hal_synthio_synthesizer_press(synthio_synthesizer_obj_t *self, mp_ob
     mp_obj_t iterable = mp_getiter(to_press, &iter_buf);
     mp_obj_t note_obj;
     while ((note_obj = mp_iternext(iterable)) != MP_OBJ_STOP_ITERATION) {
+        note_obj = validate_note(note_obj);
         if (!mp_obj_is_small_int(note_obj)) {
             synthio_note_obj_t *note = MP_OBJ_TO_PTR(note_obj);
             synthio_note_start(note, self->synth.sample_rate);
         }
-        synthio_span_change_note(&self->synth, SYNTHIO_SILENCE, validate_note(note_obj));
+        synthio_span_change_note(&self->synth, SYNTHIO_SILENCE, note_obj);
     }
 }