[Bug] Fix compilation error when defining QUICK_TAP_TERM_PER_KEY (#19893)

Author: precondition

quantum/action_tapping.c

@@ -122,7 +122,7 @@ void action_tapping_process(keyrecord_t record) {
  * readable. The conditional definition of tapping_keycode and all the
  * conditional uses of it are hidden inside macros named TAP_...
  */
-#    if (defined(AUTO_SHIFT_ENABLE) && defined(RETRO_SHIFT)) || defined(PERMISSIVE_HOLD_PER_KEY) || defined(QUICK_TAP_TERM_PER_KEY) || defined(HOLD_ON_OTHER_KEY_PRESS_PER_KEY)
+#    if (defined(AUTO_SHIFT_ENABLE) && defined(RETRO_SHIFT)) || defined(PERMISSIVE_HOLD_PER_KEY) || defined(HOLD_ON_OTHER_KEY_PRESS_PER_KEY)
 #        define TAP_DEFINE_KEYCODE uint16_t tapping_keycode = get_record_keycode(&tapping_key, false)
 #    else
 #        define TAP_DEFINE_KEYCODE

tests/tap_hold_configurations/quick_tap/config.h

@@ -19,3 +19,7 @@
 #include "test_common.h"
 
 #define QUICK_TAP_TERM 100
+// Although a seemingly superfluous addition since the default per-key function behaves
+// no differently from defining a single global QUICK_TAP_TERM, this has been useful
+// to catch compilation errors and prevent regressions in the future; see PR #19893.
+#define QUICK_TAP_TERM_PER_KEY