fix(networking): Allow configuring guest network when there is more than one interface attached

[taru-garg-hashicorp]

This change enables guest network configuration even when multiple network interfaces are present. Previously, the logic for parsing nmcli -t c show output assumed only one interface, causing failures when multiple lines were returned. The updated code now correctly handles multi-line nmcli output by first splitting it into individual lines and then processing only the non-empty ones.

Closes: #13685

[chrisroberts]

This changeset looks great! All the comments left are simply around styling (and adding a doc header). The styling comments are based on this document which includes some explanations for the various style preferences.

[Copilot]

Pull Request Overview

Enables guest network configuration when multiple network interfaces are present by parsing multi-line nmcli output.

• Refactored inline parsing into a dedicated get_current_devices method
• Updated tests to cover multi-line and empty-line outputs, and improved regex escaping
• Integrated new helper into configure_network_manager

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.

File	Description
lib/vagrant/util/guest_networks.rb	Extracted NMCLI parsing into get_current_devices and updated configure_network_manager to use it
test/unit/vagrant/util/guest_networks_spec.rb	Added specs for get_current_devices and improved IP regex matching in existing tests

Comments suppressed due to low confidence (1)

test/unit/vagrant/util/guest_networks_spec.rb:149

• Add a test case for single-line nmcli output (e.g., one device) to ensure the method handles that scenario correctly.

  describe ".get_current_devices" do

[chrisroberts]

Looks great! 👍