feat: add test hint for grant moderator availability

react/features/base/testing/components/TestConnectionInfo.js

                 <TestHint
                     id = 'org.jitsi.meet.conference.joinedState'
                     value = { this.props._conferenceJoinedState } />
+                <TestHint
+                    id = 'org.jitsi.meet.conference.grantModeratorAvailable'
+                    value = { true } />
                 <TestHint
                     id = 'org.jitsi.meet.conference.localParticipantRole'
                     value = { this.props._localUserRole } />
  *
  * @param {Object} state - The Redux state.
  * @private
- * @returns {{
- *     _conferenceConnectionState: string,
- *     _conferenceJoinedState: string,
- *     _localUserId: string,
- *     _testMode: boolean
- * }}
+ * @returns {Props}
  */
 function _mapStateToProps(state) {
     const conferenceJoined