Don't show legend on overview chart with only one unlabelled entry

 - Legacy-Id: 13268

Author: OleLaursen

ietf/stats/views.py

@@ -924,6 +924,7 @@ def get_country_mapping(registrations):
 
     return render(request, "stats/meeting_stats.html", {
         "chart_data": mark_safe(json.dumps(chart_data)),
+        "use_legend": chart_data and chart_data[0].get("name"),
         "piechart_data": mark_safe(json.dumps(piechart_data)),
         "table_data": table_data,
         "stats_title": stats_title,

ietf/templates/stats/meeting_stats_overview.html

@@ -15,12 +15,14 @@ <h3>{{ stats_title }}</h3>
              animation: false
          }
      },
+     {% if use_legend %}
      legend: {
          align: "right",
          verticalAlign: "middle",
          layout: "vertical",
          enabled: true
      },
+     {% endif %}
      title: {
          text: '{{ stats_title|escapejs }}'
      },