Add missing prototype for get_hold_on_other_key_press to resolve #18855 (#19056)

Closes undefined

quantum/action_tapping.h

@@ -40,6 +40,7 @@ bool     get_permissive_hold(uint16_t keycode, keyrecord_t *record);
 bool     get_ignore_mod_tap_interrupt(uint16_t keycode, keyrecord_t *record);
 bool     get_tapping_force_hold(uint16_t keycode, keyrecord_t *record);
 bool     get_retro_tapping(uint16_t keycode, keyrecord_t *record);
+bool     get_hold_on_other_key_press(uint16_t keycode, keyrecord_t *record);
 
 #ifdef DYNAMIC_TAPPING_TERM_ENABLE
 extern uint16_t g_tapping_term;