partially_update_objects default value is tied to object_id_field

Problem/Motivation

The default value for partially_update_objects is pulled from another field object_id_field, see the default value:

  $form['options']['partially_update_objects'] = [
    '#type' => 'checkbox',
    '#title' => t('Partially update objects'),
    '#default_value' => $index->getOption('object_id_field', FALSE),
    '#weight' => 1,
    '#description' => t('Update populated fields instead of replacing the entire object.'),
  ];

This means you can't enable partially update objects without setting a custom ID field.

You should be able to enable partially_update_objects without object_id_field.

Steps to reproduce

Try setting partially_update_objects without setting object_id_field, then revisit the settings form, it will display the default value of object_id_field, disabling partially_update_objects.

Proposed resolution

change the default value to use partially_update_objects

Remaining tasks

User interface changes

API changes

Data model changes