Move wstring to string conversion to StringUtils.cpp and update most HID get serial number functions to use it

Controllers/AnnePro2Controller/AnnePro2Controller.cpp

@@ -10,6 +10,7 @@
 \*---------------------------------------------------------*/
 
 #include "AnnePro2Controller.h"
+#include "StringUtils.h"
 
 using namespace std::chrono_literals;
 
@@ -39,10 +40,7 @@ std::string AnnePro2Controller::GetSerialString()
         return("");
     }
 
-    std::wstring return_wstring = serial_string;
-    std::string return_string(return_wstring.begin(), return_wstring.end());
-
-    return(return_string);
+    return(StringUtils::wstring_to_string(serial_string));
 }
 
 void AnnePro2Controller::SendDirect(unsigned char frame_count, unsigned char * frame_data)