FIX: correctly implements average for reports (#13447)

- Also now marks time_to_first_response as an averaged chart
- Averaged charts will now be marked as such in the UI

app/assets/javascripts/admin/addon/models/report.js

@@ -569,6 +569,13 @@ Report.reopenClass({
           !date.isSame(currentStart) &&
           !date.isBetween(currentStart, currentEnd)
         ) {
+          if (model.average) {
+            const days = currentEnd.diff(currentStart, "day") + 1; // 1 to include start
+            transformedData[currentIndex].y = parseFloat(
+              (transformedData[currentIndex].y / days).toFixed(2)
+            );
+          }
+
           currentIndex += 1;
           currentStart = currentStart.add(1, kind).startOf(isoKind);
           currentEnd = currentEnd.add(1, kind).endOf(isoKind);

app/assets/javascripts/admin/addon/templates/components/admin-report.hbs

@@ -131,6 +131,11 @@
             {{/if}}
 
             {{#if isChartMode}}
+              {{#if model.average}}
+                <span class="average-chart">
+                  {{i18n "admin.dashboard.reports.average_chart_label"}}
+                </span>
+              {{/if}}
               <div class="chart-groupings">
                 {{#each chartGroupings as |chartGrouping|}}
                   {{d-button