refactor: Change shutdownExistingProcesses to static in MSWindowsWatchdog

src/lib/platform/MSWindowsWatchdog.h

@@ -80,11 +80,6 @@ private:
    */
   void outputLoop(void *);
 
-  /**
-   * @brief Stops any core processes which were not started by the watchdog.
-   */
-  void shutdownExistingProcesses();
-
   /**
    * @brief Duplicates the process token for the given process.
    *
@@ -145,6 +140,11 @@ private:
    */
   static std::string processStateToString(ProcessState state);
 
+  /**
+   * @brief Stops any core processes which were not started by the watchdog.
+   */
+  static void shutdownExistingProcesses();
+
 private:
   Thread *m_thread = nullptr;
   bool m_running = true;