message: fix bug if metrics.endpointsRequests is missing
diff: </table>
  <h3>Endpoints requests (time in millisecond)</h3>
  - <div class="table-responsive" *ngIf="!updatingMetrics">
  + <div class="table-responsive" *ngIf="!updatingMetrics && metrics && metrics.endpointsRequests">
  <table class="table table-striped">
  <thead>
  <tr>
  