MDL-73511 mod_bigbluebuttonbn: exception raised when editing activity

* When editing an activity and the voicebridge_editable is set, there is an exception raised

mod/bigbluebuttonbn/mod_form.php

@@ -667,12 +667,12 @@ private function bigbluebuttonbn_mform_add_block_schedule(MoodleQuickForm &$mfor
      * @param string|null $descriptionkey
      * @param mixed|null $defaultvalue
      * @param array|null $options
-     * @param string|null $rule
+     * @param array|null $rule
      * @return void
      * @throws coding_exception
      */
     private function bigbluebuttonbn_mform_add_element(MoodleQuickForm &$mform, string $type, string $name, ?string $datatype,
-        ?string $descriptionkey = "", $defaultvalue = null, ?array $options = null, ?string $rule = null): void {
+        ?string $descriptionkey = "", $defaultvalue = null, ?array $options = null, ?array $rule = null): void {
         $datatype = $datatype ?? 'hidden';
         if ($type === 'hidden' || $type === 'static') {
             $mform->addElement($type, $name, $defaultvalue);

mod/bigbluebuttonbn/tests/behat/edit_instance.feature

@@ -0,0 +1,30 @@
+@mod @mod_bigbluebuttonbn @javascript
+Feature: I can edit a bigbluebutton instance
+When a bibluebutton instance has been created I can edit it
+
+  Background:  Make sure that a course is created
+    Given a BigBlueButton mock server is configured
+    And the following config values are set as admin:
+      | bigbluebuttonbn_voicebridge_editable | 1 |
+    And the following "courses" exist:
+      | fullname    | shortname   | category |
+      | Test course | Test course | 0        |
+
+  Scenario Outline: Add a mod_bigbluebuttonbn instance with Room/Activity with recordings
+    Then I log in as "admin"
+    And I am on "Test course" course homepage with editing mode on
+    When I add a "BigBlueButton" to section "1" and I fill the form with:
+      | name                   | <activityname> |
+      | Instance type          | <instancetype> |
+      | Virtual classroom name | <activityname> |
+    Given I am on the "<activityname>" "bigbluebuttonbn activity" page logged in as admin
+    And I click on "Settings" "link"
+    And the field "Instance type" matches value "<instancetype>"
+    And I <shouldseerole> "Role assigned during live session"
+    And I expand all fieldsets
+    And I <shouldseesession> "Session can be recorded"
+    Examples:
+      | activityname            | instancetype                  | shouldseerole  | shouldseesession |
+      | Activity with recording | Room/Activity with recordings | should see     | should see       |
+      | Activity only           | Room/Activity only            | should see     | should see       |
+      | Recordings only         | Recordings only               | should not see | should not see   |