function linkWithPopup(dispatch, firebase, credential) {
  return linkWithAuthDispatch(
    firebase.auth().currentUser.linkWithPopup,
    [credential],
    dispatch,
    firebase
  )
}
Links the user account with the given credentials. Internally
calls `firebase.auth().currentUser.linkWithPopup`.
@param {Function} dispatch - Action dispatch function
@param {object} firebase - Internal firebase object
@param {object} credential - Credential with which to link user account
@returns {Promise} Resolves with auth