Fix beacon summary aggregate

[ghost]

Description

This PR fixes the ordering of transaction during synchronization of the missed transactions in the self-repair when a node joins after some time of network liveness.

The issue resolved is not present on docker-compose or local node environment, but only when a node joins after a first one is there for several minutes.

The issue was about the aggregation of beacon summaries

Fixes #287

Type of change

Please delete options that are not relevant.

• Bug fix (non-breaking change which fixes an issue)

How Has This Been Tested?

• Start a node using iex -S mix
• After several 5/10 min, start another using: ARCHETHIC_P2P_PORT=3005 ARCHETHIC_HTTP_PORT=4005 ARCHETHIC_CRYPTO_SEED="node2" iex -S mix
• The transaction should be synchronized without the :invalid_proof_of_election error

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own 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