Add code to file functions.php of child theme or theme use:
function lap_gravity_forms_shop_manager_role(){
$role = get_role('shop_manager');
// remove full access in case it was added previously
$role->remove_cap('gform_full_access');
$role->add_cap('gravityforms_view_entries');
$role->add_cap('gravityforms_edit_entries');
}
add_action('admin_init','lap_gravity_forms_shop_manager_role');
Add more custom Capability list https://docs.gravityforms.com/role-management-guide/#h-gravity-forms-capabilities