This is an internal detail of the ECC arithmetic implementation, only
exposed for the sake of the unit tests
Mbed TLS 3.4.0 was released with the type mbedtls_ecp_modulus_type defined
in a public header, but without Doxygen documentation, and without any
public function or data structure using it. So removing it is not an API
break.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>