Fix narwhal dependency with net updates

[asonnino]

It seems we had the following problem twice:

• We make updates on the narwhal repo that break shared object support on Sui. We have no way to check that on the Narwhal side since the narwhal repo does not import the sui repo
• We make updates on the Sui repo that break shared object but without systematic test failures, the unit tests only become flaky.
• We eventually disable the flaky unit tests
• We add new features to narwhal that we want to import on Sui, so we update the narwhal dependency
• Shared object support is now entirely broken

This PR fixes shared object support (on both the Narwhal and Sui side) while preserving all the new Narwhal features. It also provides tests that (should) systematically breaks when we make a mistake on Sui.

This PR however does not prevent us from making updates on Narwhal that will break shared object support on Sui. @lxfind suggested that I give a tech presentation about what we need from narwhal to support shared objects on Sui, so that we can keep it in mind while updating Narwhal.

[huitseeker]

This looks great! Thanks a lot!

@lxfind suggested that I give a tech presentation about what we need from narwhal to support shared objects on Sui, so that we can keep it in mind while updating Narwhal.

That's an excellent idea!