[launch] Mount options silently dropped on timeout

[tobe2098]

Describe the bug
The mount options are silently dropped on timeout

To Reproduce
How, and what happened?

1. multipass launch -n a --timeout 5 --mount ~/dir:/mnt/dir
2. Error does not mention the missed mounts, even if the instance eventually reaches the running state.

Expected behavior
Multipass should clarify to the user that the mount flags are dropped if the mount initialization part is not reached.

Additional info

• OS: Ubuntu 24.04
• CPU architecture or model: amd64
• multipass version: 1.17.0-dev

[NiShITa-code]

I’d like to investigate this issue and work on a fix.

[tobe2098]

Very well, look into this, but the merge of #4663 may be useful here.