Use logic in Z_SAFE_HOMING

Use logic in Z_SAFE_HOMING

From
```
if (home_all_axis || homeZ) {
  if (home_all_axis) {
  ...
  home z
  }
  else if (homeZ) { // Don't need to Home Z twice
  home z
  }
}

```
to
```
if (home_all_axis || homeZ) {
  if (home_all_axis) {
  ...
  }
  home z
}
```

Marlin/Marlin_main.cpp

@@ -3015,13 +3015,8 @@ inline void gcode_G28() {
              */
             current_position[X_AXIS] = destination[X_AXIS];
             current_position[Y_AXIS] = destination[Y_AXIS];
-
-            // Home the Z axis
-            HOMEAXIS(Z);
           }
 
-          else if (homeZ) { // Don't need to Home Z twice
-
           // Let's see if X and Y are homed
           if (axis_unhomed_error(true, true, false)) return;
 
@@ -3044,7 +3039,6 @@ inline void gcode_G28() {
             SERIAL_ECHO_START;
             SERIAL_ECHOLNPGM(MSG_ZPROBE_OUT);
           }
-          } // !home_all_axes && homeZ
 
           #if ENABLED(DEBUG_LEVELING_FEATURE)
             if (DEBUGGING(LEVELING)) {