Don't run `M600` on filament runout if the nozzle is cold

Marlin/src/Marlin.cpp

 void manage_inactivity(bool ignore_stepper_queue/*=false*/) {
 
   #if ENABLED(FILAMENT_RUNOUT_SENSOR)
-    if ((IS_SD_PRINTING || print_job_timer.isRunning()) && (READ(FIL_RUNOUT_PIN) == FIL_RUNOUT_INVERTING))
+    if ((IS_SD_PRINTING || print_job_timer.isRunning())
+      && READ(FIL_RUNOUT_PIN) == FIL_RUNOUT_INVERTING
+      && thermalManager.targetHotEnoughToExtrude(active_extruder)
+    )
       handle_filament_runout();
   #endif