[Fix]: ISigner Only sign consensus messages

[Wi1l-B0t]

Description

Fix an issue found in #3896.

The current ISigner interface can sign any data and there is an issue if the data is a tranfer tx.

This PR allows the signer to only sign consensus messages and block.

Fixes # (issue)

Type of change

• Optimization (the change is only an optimization)
• Style (the change is only a code style for better maintenance or standard purpose)
• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published in downstream modules

[shargon]

I don't see the problem of signany data, it should be the implementation who make the restrictions, so it should be good to have different methods for different kind of signatures

[Wi1l-B0t]

I don't see the problem of signany data, it should be the implementation who make the restrictions, so it should be good to have different methods for different kind of signatures

the problem of sign any data

If an attacker hacked a neo node that uses this sign service(If no this sign service, the attacker can get the privat key), the attacker can send a tx to the sign service, and if sign service sign this tx data, the assets will be transferred.

different methods for different kind of signatures

What is "different methods for different kind of signatures"?

[shargon]

What is "different methods for different kind of signatures"?

SignTransaction, SignConsensus the signer can throw an excenption on SignTransaction if they don't want to allow it

[Wi1l-B0t]

What is "different methods for different kind of signatures"?

SignTransaction, SignConsensus the signer can throw an excenption on SignTransaction if they don't want to allow it

SignTransaction is not used now, so not added.
SignConsensus is SignExtensiblePayload here.

[vncoelho]

Looks good to me