virtual_network/migrate_with_bridge: enable remote host iface config

[smitterl]

This PR reopens #6717 which was accidentally merged and then reverted because dependency avocado-framework/avocado-vt#4280 hadn't been merged yet.

Once the dependency has been merged this one can be merged too as it already got all the relevant approvals.

Description:

We previously enabled configuration for host face selection for bridge setup to account for environments where it's not the default interface (the first one). However, the test case also requires this for the remote host as it's a migration test case.

Add this option and the same setting logic as for 'host_iface'.

Summary by CodeRabbit

• Tests

  • Enhanced virtual network migration test configuration with remote host interface support.

• Chores

  • Refactored test code for improved consistency and maintainability through formatting standardization.

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[coderabbitai]

Walkthrough

This pull request adds a new configuration parameter remote_host_iface to a network migration test configuration file. The corresponding Python source file is updated to recognize and handle this parameter during test setup and teardown phases. Changes consist primarily of formatting adjustments (quote style normalization, indentation alignment, multi-line wrapping) and parameter passing refactoring for consistency. The remote_host_iface value is computed from the SSH session when not explicitly provided and propagated through the test flow. No functional behavior modifications are reported.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~12 minutes

🚥 Pre-merge checks | ✅ 3

✅ Passed checks (3 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly and specifically describes the main change: enabling remote host interface configuration for the migrate_with_bridge test case.
Docstring Coverage	✅ Passed	Docstring coverage is 100.00% which is sufficient. The required threshold is 80.00%.

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✨ Finishing touches

• 📝 Generate docstrings

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[smitterl]

See description, dependency has been merged, merge this too