Simpler decorators removal from `ProvenTransaction` and `ProvenBatch`

[SantiagoPittella]

In 0xMiden/node#1194 the decorators removal in received ProvenTransaction and ProvenBatch was added, but due to the lack of accessors and mutators to the MAST of the note script we needed to dismember the original structs to then change the MAST and rebuild the, now without decorators` struct.

We need to investigate for a way to remove decorators easier from the mentioend structs, without having to clone so much and less error-prone.

[Mirko-von-Leipzig]

@SantiagoPittella this is probably more of an issue for the protocol? Should we move it?

[SantiagoPittella]

Yes, makes sense 👍🏼

[PhilippGackstatter]

The approach for output notes in #2205 is to strip decorators from NoteScript at the proving boundary, e.g. when ExecutedTransaction becomes ProvenTransaction . Maybe the same pattern could apply to (public) AccountCode.