message: packages/core: add logout item to user settings in sidebar
diff: import React, { useContext, useEffect } from 'react';
  import Collapse from '@material-ui/core/Collapse';
  import Star from '@material-ui/icons/Star';
  +import SignOutIcon from '@material-ui/icons/MeetingRoom';
  import { SidebarContext } from './config';
  -import { googleAuthApiRef, githubAuthApiRef } from '@backstage/core-api';
  +import {
  + googleAuthApiRef,
  + githubAuthApiRef,
  + identityApiRef,
  + useApi,
  +} from '@backstage/core-api';
  import {
  OAuthProviderSettings,
  OIDCProviderSettings,
  UserProfile as SidebarUserProfile,
  } from './Settings';
  +import { SidebarItem } from './Items';
  export function SidebarUserSettings() {
  const { isOpen: sidebarOpen } = useContext(SidebarContext);
  const [open, setOpen] = React.useState(false);
  + const identityApi = useApi(identityApiRef);
  // Close the provider list when sidebar collapse
  useEffect(() => {
  @@ -48,6 +56,11 @@ export function SidebarUserSettings() {
  apiRef={githubAuthApiRef}
  icon={Star}
  />
  + <SidebarItem
  + icon={SignOutIcon}
  + text="Sign Out"
  + onClick={() => identityApi.logout()}
  + />
  </Collapse>
  </>
  );
  