Allow resume from pause with parking enabled (#12893)

Currently, Pause of an SD-Memory card print does not work.    This has been verified to resolve the issue by multiple people.   

I understand more work needs to be done to resolve some of the concerns...

Marlin/src/gcode/sdcard/M20-M30_M32-M34_M524_M928.cpp

@@ -114,13 +114,15 @@ void GcodeSuite::M24() {
  * M25: Pause SD Print
  */
 void GcodeSuite::M25() {
+  
+  // Set initial pause flag to prevent more commands from landing in the queue while we try to pause
+  #if ENABLED(SDSUPPORT)
+    if (IS_SD_PRINTING()) { card.pauseSDPrint(); }
+  #endif
+
   #if ENABLED(PARK_HEAD_ON_PAUSE)
     M125();
   #else
-    #if ENABLED(SDSUPPORT)
-      if (IS_SD_PRINTING()) card.pauseSDPrint();
-    #endif
-
     print_job_timer.pause();
     ui.reset_status();