Fix Z4 stepper indirection macros (#17107)

Marlin/src/module/stepper/indirection.h

   #ifndef Z4_ENABLE_INIT
     #define Z4_ENABLE_INIT() SET_OUTPUT(Z4_ENABLE_PIN)
     #define Z4_ENABLE_WRITE(STATE) WRITE(Z4_ENABLE_PIN,STATE)
-    #define Z4_ENABLE_READ() READ(Z4_ENABLE_PIN)
+    #define Z4_ENABLE_READ() bool(READ(Z4_ENABLE_PIN))
   #endif
   #ifndef Z4_DIR_INIT
     #define Z4_DIR_INIT() SET_OUTPUT(Z4_DIR_PIN)
     #define Z4_DIR_WRITE(STATE) WRITE(Z4_DIR_PIN,STATE)
-    #define Z4_DIR_READ() READ(Z4_DIR_PIN)
+    #define Z4_DIR_READ() bool(READ(Z4_DIR_PIN))
   #endif
-  #define Z4_STEP_INIT SET_OUTPUT(Z4_STEP_PIN)
+  #define Z4_STEP_INIT() SET_OUTPUT(Z4_STEP_PIN)
   #ifndef Z4_STEP_WRITE
     #define Z4_STEP_WRITE(STATE) WRITE(Z4_STEP_PIN,STATE)
   #endif
-  #define Z4_STEP_READ READ(Z4_STEP_PIN)
+  #define Z4_STEP_READ() bool(READ(Z4_STEP_PIN))
 #else
   #define Z4_DIR_WRITE(STATE) NOOP
 #endif