db: revert registration upgrade; fix tables that upgraded

The registration field definition was unintentionally changed. Some users upgraded after that change and have the wrong database column settings. After upgrading again, those users will have the correct column settings.

db/upgrade.php

@@ -874,7 +874,7 @@ function xmldb_zoom_upgrade($oldversion) {
         $table = new xmldb_table('zoom');
 
         // Define and conditionally add field registration.
-        $field = new xmldb_field('registration', XMLDB_TYPE_INTEGER, '1', null, null, null, null, 'option_auto_recording');
+        $field = new xmldb_field('registration', XMLDB_TYPE_INTEGER, '1', null, XMLDB_NOTNULL, null, '2', 'option_auto_recording');
         if (!$dbman->field_exists($table, $field)) {
             $dbman->add_field($table, $field);
         }
@@ -933,5 +933,19 @@ function xmldb_zoom_upgrade($oldversion) {
         upgrade_mod_savepoint(true, 2023111600, 'zoom');
     }
 
+    if ($oldversion < 2024012700) {
+        $table = new xmldb_table('zoom');
+        $field = new xmldb_field('registration', XMLDB_TYPE_INTEGER, '1', null, XMLDB_NOTNULL, null, '2', 'option_auto_recording');
+
+        // Launch change of notnull for field registration.
+        $dbman->change_field_notnull($table, $field);
+
+        // Launch change of default for field registration.
+        $dbman->change_field_default($table, $field);
+
+        // Zoom savepoint reached.
+        upgrade_mod_savepoint(true, 2024012700, 'zoom');
+    }
+
     return true;
 }