message: Fix sparkline issue for edge leading from service and including traffic from unknown
  make sure this fix does not break the fix in kiali-1732 for TCP sparkine
  for edges leading from a service.
diff: @@ -215,10 +215,11 @@ export default class SummaryPanelEdge extends React.Component<SummaryPanelPropTy
  this.metricsPromise.promise
  .then(response => {
  + // HTTP
  let useDest = sourceData.nodeType === NodeType.UNKNOWN;
  - useDest = useDest || this.props.namespace === 'istio-system';
  - const reporter = useDest ? response.data.dest : response.data.source;
  - const metrics = reporter.metrics;
  + useDest = useDest || this.props.namespace === 'istio-system' || sourceData.nodeType === NodeType.SERVICE;
  + let reporter = useDest ? response.data.dest : response.data.source;
  + let metrics = reporter.metrics;
  const histograms = reporter.histograms;
  const reqRates = this.getNodeDataPoints(
  metrics['request_count_in'],
  @@ -262,6 +263,11 @@ export default class SummaryPanelEdge extends React.Component<SummaryPanelPropTy
  destMetricType,
  sourceData
  );
  + // TCP (uses slightly different reporting)
  + useDest = sourceData.nodeType === NodeType.UNKNOWN;
  + useDest = useDest || this.props.namespace === 'istio-system';
  + reporter = useDest ? response.data.dest : response.data.source;
  + metrics = reporter.metrics;
  const tcpSentRates = this.getNodeDataPoints(
  metrics['tcp_sent_in'],
  'Sent',
  