Allow cold Filament Load/Unload with M302 P1 (#20262)

Co-authored-by: Scott Lahteine <thinkyhead@users.noreply.github.com>

Marlin/src/feature/pause.cpp

   #endif
   UNUSED(mode);
 
-  if (wait)
-    return thermalManager.wait_for_hotend(active_extruder);
+  if (wait) return thermalManager.wait_for_hotend(active_extruder);
 
-  wait_for_heatup = true; // Allow interruption by Emergency Parser M108
+  // Allow interruption by Emergency Parser M108
+  wait_for_heatup = TERN1(PREVENT_COLD_EXTRUSION, !thermalManager.allow_cold_extrude);
   while (wait_for_heatup && ABS(thermalManager.degHotend(active_extruder) - thermalManager.degTargetHotend(active_extruder)) > TEMP_WINDOW)
     idle();
   wait_for_heatup = false;