T7391 domain search fix for 1.4+ (#418)

• t7391 init

• sanity

• vyos_system unit test

• added vyos_system v14 test cases

• vyos_system integration tests fix

• changelog

• domain search integration test

• Update plugins/modules/vyos_system.py

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

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Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>