title: Using GIS (Google Identity Services) and API Subpackage (picker) without client package
body: <p>I am currently replacing the <code>gapi.oauth2</code> package, by using the <code>TokenClient</code> according to the <a href="https://developers.google.com/identity/oauth2/web/guides/migration-to-gis" rel="noreferrer">guide</a> and everything works fine.</p>
  <p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
  <div class="snippet-code">
  <pre class="snippet-code-html lang-html prettyprint-override"><code>global.google.accounts.oauth2
          .initTokenClient({
              client_id: CONFIG.google.clientId,
              scope: 'https://www.googleapis.com/auth/drive.readonly',
              ux_mode: 'popup',
              callback(tokenResponse) {
                  if (tokenResponse &amp;&amp; !tokenResponse.error) {
                      onSuccess(tokenResponse.access_token);
  
                      return;
                  }
  
                  onError(tokenResponse.error || 'google authentication failed');
              },
          })
          .requestAccessToken({});</code></pre>
  </div>
  </div>
  </p>
  <p>The only issue is that we are not using the <code>gapi.client</code> and would prefer avoiding loading that package as we are only using the token to show a picker by using <code>google.picker.PickerBuilder</code>.
  Now after the initialization the GSI package tries to use <code>gapi.client.setToken()</code> which obviously fails as the package is not loaded.</p>
  <p><a href="https://i.stack.imgur.com/KGZjy.png" rel="noreferrer">[GSI_LOGGER-TOKEN_CLIENT]: Set token failed. Gapi.client.setToken undefined.</a></p>
  <p>So now i could not find anything in the reference on how to prevent that call to happen, nor how to at least suppress the warning by not e.g hacking in a <code>noop</code> as a placeholder.</p>
  <p>Does anyone know if there is any official way to deal with that ?</p>