feat: Let addrman handle multiple ports for all networks

[UdjinM6]

Issue being fixed or feature implemented

There is really no need to do have this restriction in addrman, we check AllowMultiplePorts() in connman which should be enough already. We can safely re-align addrman to its upstream implementation as suggested in #6043.

What was done?

Drop port "discrimination" in addrman, remove related tests.

How Has This Been Tested?

Run tests, run dash-qt on mainnet/testnet

Breaking Changes

n/a

Checklist:

• [x] 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
• [x] I have assigned this pull request to a milestone (for repository code-owners and collaborators only)

[UdjinM6]

It changes the internals of addrman logic so not a refactor imo. feat maybe?