Update Search trait for per_page & page attributes
Update Search trait for per_page & page attributes

Based on the examples below from the Moneybird Docs, the search trait can be updated to allow `per_page` & `page` as an attribute:
- https://developer.moneybird.com/api/contacts/#get_contacts_example2
- https://developer.moneybird.com/api/products/#get_products_example3
picqer/moneybird-php-client