Re-deploy the Foundation DNS Seeders

[teor2345]

Is your feature request related to a problem? Please describe.

After #1709 and #1721 are merged, our DNS seeders will be a lot more accurate and reliable.

Describe the solution you'd like

• Wait for PR Fix candidate set address state handling #1709 and Refactor connection.rs to make fail_with errors impossible #1721 to merge
• Rebuild our DNS seeders with the latest zebra-network version
• Redeploy our DNS seeders

Describe alternatives you've considered

Do nothing: our DNS seeders might be unreliable.

Additional context

This change helps stabilise testnet and mainnet.

[teor2345]

I've tentatively scheduled this task for sprint 5, because:

• there's some redundancy in the Zcash DNS seeders, because the ECC and other individuals also operate seeders
• we want to make sure zebra-network is stable before we put effort into re-deployment
• we're already thinking about another Zebra deployment task for sprint 4 (Deploy more Zebra or zcashd instances on testnet #1222)

[teor2345]

The DNS seeders don't use zebra-network, so this ticket is invalid.