Warn on mounting volumes locally

[kramstrom]

Describe your changes

• MOD-3103 warn users when attempting to mount volumes locally as it's a common source of confusion

Backward/forward compatibility checks

--- Check these boxes or delete any item (or this section) if not relevant for this PR. - [ ] Client+Server: this change is compatible with old servers - [ ] Client forward compatibility: this change ensures client can accept data intended for later versions of itself Note on protobuf: protobuf message changes in one place may have impact to multiple entities (client, server, worker, database). See points above. ---

Changelog

[mwaskom]

Also, is there a Linear issue that we could link this to?

[kramstrom]

Also, is there a Linear issue that we could link this to?

I added the issue in the branch name but also wrote it in the pr body now :)