Add support to choose VM for start app

[avnik]

Description

Add ability to specify VM to run application (by @mbssrc suggestion)
Also adjust tests to recent changes in main branch

Checklist

• Summary of the proposed changes in the PR description
• More detailed description in the commit message(s)
• Commits are squashed into relevant entities - avoid a lot of minimal dev time commits in the PR
• Contribution guidelines followed
• Test procedure added to nixos/tests
• Author has run nix flake check --accept-flake-config and it passes
• All automatic Github Action checks pass - see actions
• Author has added reviewers and removed PR draft status

Testing

[mbssrc]

As this is a quickfix, let's get this merged now, while you are re-coding the request parameters.
Fixed version here: eacbac0 , please double check