Pass timeout from daemon to backend operations

Currently there are [places](https://github.com/canonical/multipass/blob/0c58deb74c38bfc364311cae38b4b14b3646fec9/src/platform/backends/lxd/lxd_virtual_machine.cpp#L189) where we should be passing the timeout from the daemon when doing backend operations. Another candidate for this would be https://github.com/canonical/multipass/pull/2935.

Start with src/platform/backends/lxd/lxd_virtual_machine.cpp around line 189, then review the timeout flow in pull request #2935. Trace which daemon-triggered backend operations are in scope and identify how completion should demonstrate that the daemon timeout is propagated consistently.

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