```
Tx-inv messages are ignored during IBD, so it would be nice if we told
peers to not send them in the first place. Do that by sending two
feefilter messages: One when the connection is made (and the node is in
IBD), and another one when the node leaves IBD.
```
Backport of [[https://github.com/bitcoin/bitcoin/pull/19204 | core#19204]].