Handle issue of converting timestamp to local date time rather than other datetime in graph_visualization.py

[ravishende]

In gpu_dashboard, if you specify display_timestamp_as_datetime=True in get_graphs_from_queries, it will show th correct local time. But, if you say that is false, then run display_graphs(), passing in graphs_dict, it will display a time that is a few hours off from local time.

Also handle if they pass in display_timestamp_as_datetime=True, then put that graphs_dict into display_graphs()