field_group_link Link formatter settingsForm() signature incompatible with field_group #3495221

Problem/Motivation

After applying the field_group patch from issue #3495221
("Add $form and $form_state parameters to formatter plugins' settingsForm method"),
Drupal throws a fatal error:

Fatal error: Declaration of
Drupal\field_group_link\Plugin\field_group\FieldGroupFormatter\Link::settingsForm()
must be compatible with
Drupal\field_group\FieldGroupFormatterBase::settingsForm(array $form,
Drupal\Core\Form\FormStateInterface $form_state) in
/web/modules/contrib/field_group_link/src/Plugin/field_group/FieldGroupFormatter/Link.php
on line 116

This is because the `Link` formatter class in `field_group_link` still uses the
old `settingsForm()` signature without parameters, while `field_group` has updated
`FieldGroupFormatterBase::settingsForm()` to require `array $form` and
`FormStateInterface $form_state` parameters.

Steps to reproduce

1. Apply patch #3495221 to `drupal/field_group`
2. Have `drupal/field_group_link` installed
3. Clear cache
4. Navigate to any Manage Display page that uses the Link field group formatter

Proposed resolution

Update `Link::settingsForm()` signature and parent call to match the new
`FieldGroupFormatterBase` signature:

// Before
public function settingsForm() {
  $form = parent::settingsForm();

// After
public function settingsForm(array $form, \Drupal\Core\Form\FormStateInterface $form_state) {
  $form = parent::settingsForm($form, $form_state);

Related issues

- field_group #3495221: Add $form and $form_state parameters to formatter plugins'
settingsForm method