UI: Initialize Stats window values after OBSInit/reset

When the statistics window starts up for the first time, it reset values
at that very moment so that stray lagged frames due to OBS' startup
wouldn't be displayed.  However, that's really a bad place to reset
those values because the user could want to view the stats window after
a long stream, and having those values reset when he/she views the
window for the first time would sort of make the point of viewing your
stats moot.

Instead, reset the values only when applicable, such as after OBSInit or
when video is reset.

UI/window-basic-main.cpp

@@ -1463,6 +1463,8 @@ void OBSBasic::OBSInit()
 
 	if (config_get_bool(basicConfig, "General", "OpenStatsOnStartup"))
 		on_stats_triggered();
+
+	OBSBasicStats::InitializeValues();
 }
 
 void OBSBasic::InitHotkeys()
@@ -2772,6 +2774,8 @@ int OBSBasic::ResetVideo()
 			ResizeProgram(ovi.base_width, ovi.base_height);
 	}
 
+	OBSBasicStats::InitializeValues();
+
 	return ret;
 }