message: Don't allow detail graph of unused node
  also, change invalid  drill-down from ERROR to WARNING message
diff: @@ -38,8 +38,8 @@ import {
  } from '../../types/Graph';
  import { EdgeLabelMode, Layout } from '../../types/GraphFilter';
  import * as H from '../../types/Health';
  +import { MessageType } from '../../types/MessageCenter';
  import { NamespaceAppHealth, NamespaceServiceHealth, NamespaceWorkloadHealth } from '../../types/Health';
  -
  import { GraphUrlParams, makeNodeGraphUrlFromParams } from '../Nav/NavUtils';
  import { NamespaceActions } from '../../actions/NamespaceAction';
  import { DurationInSeconds, PollIntervalInMs } from '../../types/Common';
  @@ -503,13 +503,22 @@ export class CytoscapeGraph extends React.Component<CytoscapeGraphProps, Cytosca
  if (targetType !== 'node' && targetType !== 'group') {
  return;
  }
  -
  if (target.data(CyNode.isInaccessible)) {
  return;
  }
  if (target.data(CyNode.hasMissingSC)) {
  MessageCenterUtils.add(
  - `A node with a missing sidecar provides no node-specific telemetry and can not provide a node detail graph.`
  + `A node with a missing sidecar provides no node-specific telemetry and can not provide a node detail graph.`,
  + undefined,
  + MessageType.WARNING
  + );
  + return;
  + }
  + if (target.data(CyNode.isUnused)) {
  + MessageCenterUtils.add(
  + `An unused node has no node-specific traffic and can not provide a node detail graph.`,
  + undefined,
  + MessageType.WARNING
  );
  return;
  }
  