bug: key with invalid format during import over RPC provides unhelpful error message

### 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/kubo/issues?q=is%3Aissue) for my bug.
- [X] I am running the latest [kubo version](https://dist.ipfs.tech/#kubo) or have an issue updating.

### Installation method

ipfs-update or dist.ipfs.tech

### Version

_No response_

### Config

_No response_

### Description

see
* https://github.com/ipfs/js-kubo-rpc-client/pull/83#discussion_r1050028237
* https://github.com/ipfs/js-kubo-rpc-client/issues/56
* https://github.com/ipfs/js-ipfs/issues/3547

Error seen is "HTTPError: file argument 'key' is required" even when providing the correct parameters, but an invalid key format. We should recognize the argument, but display error on format if that is truly the case.