Consider making `MLK_CONFIG_NO_SUPERCOP` implicit when `MLK_CONFIG_MULTILEVEL_BUILD` set

[mkannwischer]

Defining the SUPERCOP API (crypto_kem_enc etc.) when multiple parameter sets are built does not make sense.
The documentation even states:

 *              NOTE: You must set this for a multi-level build as the SUPERCOP
 *              naming does not disambiguate between the parameter sets.

Now that we have MLK_CONFIG_MULTILEVEL_BUILD, we might as well set this implicitly.
We forgot to set it in

mlkem-native/examples/multilevel_build/mlkem_native/mlkem_native_config.h

Line 158 in 15b1eb1

/* #define MLK_CONFIG_NO_SUPERCOP */

- which led to problems with pq-code-package/mldsa-native#869.

[hanno-becker]

Agree