Allows to get how many users have already set the given permission defined by permission_id.
INVOCATION METHOD: This function allows to perform an synchronous remote invocation. for the service "af_kernel::af_user::permission_num_elements".
This function is a synchronous version for afdal_af_kernel_af_user_permission_num_elements function.
|permission_id ||The permission to check how many users the have it set. |