Flaky Peering sharness tests

### Checklist

- [X] This is a bug report, not a question. Ask questions on [discuss.ipfs.io](https://discuss.ipfs.io).
- [X] I have searched on the [issue tracker](https://github.com/ipfs/go-ipfs/issues?q=is%3Aissue) for my bug.
- [X] I am running the latest [go-ipfs version](https://dist.ipfs.io/#go-ipfs) or have an issue updating.

### Installation method

built from source

### Version

_No response_

### Config

_No response_

### Description

There are tests occasionally failing in CI coming from https://github.com/ipfs/go-ipfs/blob/master/test/sharness/t0171-peering.sh (e.g. https://app.circleci.com/pipelines/github/ipfs/go-ipfs/4912/workflows/4f788a8b-b199-439e-947b-de73032201b8/jobs/54120/tests).

A guess as to why the test might be flaky is that MDNS being enabled messes up tests like https://github.com/ipfs/go-ipfs/blob/050a281e887264cd8fe9ade0fda6f5d8dd17c166/test/sharness/t0171-peering.sh#L60-L63 since it might be that all the nodes end up connected to each other and checking for a matching first peer is a bad check. Instead we'd want to check if any of the peers we're connected to are the target, or disable MDNS so that peers only connect to the ones we instruct them to.