Align the DIDComm protocol implementation in the edge-agent SDK KMP with the DIDComm specification (optional body property)

[yshyn-iohk]

Is this a regression?

No

Description

All Aried protocols (e.g., issue credentials, present proof, revoke credentials, report a problem, etc.) should be revised according to the DIDCommV2 specification and use the body property of the DIDComm message as an optional field.

Please provide the exception or error you saw

The `body` property of the DIDComm messages must be optional
In the current version, 1.40.0, the `body` is required and contains the nested properties with `null` values.
In the version after 1.40.0, the nested properties with `null` values are dropped, and the `body` is an empty object.
Example of the message: issue-credential/3.0/issue-credential

Please provide the environment you discovered this bug in

DEV

Anything else?

Interoperability with other SSI systems and agents needs to align with the specifications and not send unnecessary properties.