In each broadcast routine, before sending a transaction, we read the
peer's state so we can compare the height of the transaction against the
peer's height. So, for each transaction we want to send, we call
`peer.Get(types.PeerStateKey).(PeerState)` that reads the (pointer to
the) peer's state. This PR makes this call once, before starting the
loop through the list of transactions. This is possible because
`PeerState` is set once (on the consensus reactor) and never unset.

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---

#### PR checklist

- [ ] Tests written/updated
- [x] Changelog entry added in `.changelog` (we use
[unclog](https://github.com/informalsystems/unclog) to manage our
changelog)
- [ ] Updated relevant documentation (`docs/` or `spec/`) and code
comments
- [X] Title follows the [Conventional
Commits](https://www.conventionalcommits.org/en/v1.0.0/) spec

---------

Co-authored-by: Anton Kaliaev <anton.kalyaev@gmail.com>
(cherry picked from commit 890c241)