fix(evidence): send evidence only once

[lklimek]

Issue being fixed or feature implemented

Right now, evidence is sent to all peers, which is not necessary and can generate huge load during chain halt.

Reproduction scenario:

1. Stop majority of chain nodes (except one)
2. Remove WAL from stopped nodes
3. Break the code so that the chain will be halted
4. Start stopped nodes

As a result, these nodes will generate huge amount of evidence messages, which will be sent to all peers repeatedly. On big enough network, this will cause significant load.

What was done?

We no longer repeatedly send evidence to all connected peers.

Instead:

1. When a peer connects, we send all evidence from the pool to it.
2. When new evidence arrives, we broadcast it to all peers.

How Has This Been Tested?

TODO

Breaking Changes

None

Checklist:

• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have added or updated relevant unit/integration/functional/e2e tests
• I have made corresponding changes to the documentation

For repository code-owners and collaborators only

• I have assigned this pull request to a milestone