Fix singlenozzle toolchange cold extrusion test

Marlin/src/module/tool_change.cpp

         #if ENABLED(SINGLENOZZLE)
 
           #if ENABLED(PREVENT_COLD_EXTRUSION)
-            if ((!DEBUGGING(DRYRUN) && thermalManager.targetTooColdToExtrude(active_extruder)) || sn_settings.swap_length == 0) {
+            if (!DEBUGGING(DRYRUN) && thermalManager.targetTooColdToExtrude(active_extruder) && sn_settings.swap_length) {
               SERIAL_ERROR_START();
               SERIAL_ERRORLNPGM(MSG_HOTEND_TOO_COLD);
               active_extruder = tmp_extruder;