Add type:civicrm-ext in composer.json

The composer.json file is missing "type": "civicrm-ext", so the extension can be installed in the directory specified using installer-paths, otherwise they're installed in vendor/ by default and CiviCRM complains that the extension is missing.

The civicrm-ext type is supported standard as per https://github.com/composer/installers?tab=readme-ov-file#current-supported-package-types.

Check nz.co.fuzion.extendedreport extension for the example.