Nomad masks / confuses error from CSI plugin

When any of `ControllerPublishVolume`, `NodePublishVolume`, and `NodeStageVolume` returns a `FailedPrecondition` error from a CSI plugin, it gets logged with an error message derived from the [CSI spec](https://github.com/container-storage-interface/spec/blob/master/spec.md#controllerpublishvolume-errors). Example:

2024-08-23T16:32:05-07:00 Setup Failure failed to setup alloc: pre-run hook "csi_hook" failed: mounting volumes: volume "85cd0978-05bf-11ef-bd6d-0242c0a82802" is already published on another node and does not have MULTI_NODE volume capability: rpc error: code = FailedPrecondition desc = volume "85cd0978-05bf-11ef-bd6d-0242c0a82802" is already staged at [/local/csi/staging/vol-madeupid1/rw-file-system-single-node-writer]

The spec certainly says that in case of a call to `PublishVolume` for an already mounted volume etc. etc., the correct return code is `FailedPrecondition`. The spec doesn't actually say that `FailedPrecondition` is only for that particular error condition, although it's a little awkwardly phrased. Regardless, a `FailedPrecondition` response to [`NodePublishVolume`](https://github.com/container-storage-interface/spec/blob/master/spec.md#nodepublishvolume-errors) or [`NodeStageVolume`](https://github.com/container-storage-interface/spec/blob/master/spec.md#nodestagevolume-errors) means something entirely different and the error shown to users is confusing.