Deleting custom fields created through a custom app on other erpnext doctype upon uninstalling the app?

Hello ERPNEXT users,

I created a custom app called (EmployeeContract), and through the (export-fixtures) I was able to export all the fixtures for the Custom Fields that is included in this new apps successfully.
In the file apps/EmployeeContract/EmployeeContract/fixtures/custom_fields.json, I have added custom fields to Doctype Employee (ERPNEXT Doctype)

Could you confirm if there is a way so that after the installation of my app I go ahead and uninstall the app on a site… all these (Custom Fields) that were created through this custom app on Employee doctype can be deleted upon app uninstall?

I appreciate your assistance