chore(core): use agent identifier in almanac attestation

[jrriehl]

Proposed Changes

In order to for the Almanac API to know whether an agent is registered on testnet or mainnet, it need to have access to the full prefixed agent identifier (test-agent://agent1..., agent://agent1...), not just the agent address.

Linked Issues

#520

Types of changes

What type of change does this pull request make (put an x in the boxes that apply)?

• Bug fix (non-breaking change that fixes an issue).
• New feature added (non-breaking change that adds functionality).
• Breaking change (fix or feature that would cause existing functionality to stop working as expected).
• Documentation update.
• Something else (e.g., tests, scripts, example, deployment, infrastructure).

Checklist

Put an x in the boxes that apply:

• I have read the CONTRIBUTING guide
• Checks and tests pass locally

If applicable

• I have added tests that prove my fix is effective or that my feature works
• I have added/updated the documentation (executed the script in python/scripts/generate_api_docs.py)

[Archento]

Looks good to me!
We just need to remember checking for compatibility with the inspector as the return value in the REST endpoint has changed.