Add 'uuid' as a default initial field and initial sort field.

[kevinquillen]

I believe this module should behave no differently than how the other backend plugins behave.

The addIndex() method was previously commented out and disabled. When creating a new index, a new collection should be made in Typesense as well.

The previous reason seemed to involve the lack of an initial field with default sort field, which Typesense requires on creating a new collection. We can simply add 'id' or 'uuid' as the first field and the sort field so the process of creating and managing an index in Search API is a bit more streamlined. All entities have a ID/UUID.

Later, we can prevent 'removal' of fields if they are set as the default sort and get it locked and try to keep the fields UI congruent to what Typesense expects at a minimum.

It currently looks something like this:

  public function addIndex(IndexInterface $index) {
    try {
      $index_fields = $index->getFields();
      $typesense_fields = [];

      if (empty($index_fields)) {
        $typesense_fields[] = [
          "name" => "id",
          "type" => "int64",
          "facet" => FALSE,
          "optional" => FALSE,
          "index" => TRUE,
          "sort" => TRUE,
          "infix" => FALSE,
          "locale" => "",
        ];
      }

      $collection_name = $index->id();
      $typesense_fields += $index_fields;

      $schema = [
        'name' => $collection_name,
        'fields' => $typesense_fields,
      ];

      $schema['default_sorting_field'] = $default_sorting_field ?? 'id';

      $this->typesense->createCollection($schema);
    } catch (SearchApiTypesenseException $e) {
      $this->logger->error($e->getMessage());
      $this->messenger()->addError($this->t('Unable to add index @index.', [
        '@index' => $collection_name,
      ]));
    }
  }

If the index has no fields, add a default one. It would be critical to also add one to the index in Drupal so its 'mapped' in the UI. This is not similar to how other backends work, but its what Typesense requires so that should not be a problem necessarily.