Init print_job_timer in setup() instead of "early" (#9937)

Marlin/src/libs/stopwatch.h

@@ -52,6 +52,11 @@ class Stopwatch {
      */
     Stopwatch();
 
+    /**
+     * @brief Initialize the stopwatch
+     */
+    inline void init() {}
+
     /**
      * @brief Stops the stopwatch
      * @details Stops the running timer, it will silently ignore the request if