Avoid message box if font load failure during startup (#8610)

Move init sys font into GUI_App, after logging has been set up properly (#8603)

This avoid annoying messagebox if somehow failed to load font on windows, and write the message into log files instead

src/slic3r/GUI/GUI_App.cpp

@@ -2202,6 +2202,8 @@ bool GUI_App::on_init_inner()
     wxLog::SetLogLevel(wxLOG_Message);
 #endif
 
+    ::Label::initSysFont();
+
     // Set initialization of image handlers before any UI actions - See GH issue #7469
     wxInitAllImageHandlers();
 #ifdef NDEBUG