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 <[email protected]>

---

Co-authored-by: Copilot <[email protected]>