test: extract reusable SV2 Connman tester

[enirox001]

Moves ConnTester out of sv2_connman_tests.cpp into a reusable test helper.

This keeps the existing SV2 Connman test behavior unchanged while making the mock DynSock client setup available to future tests.

Tested with

  cmake --build build --target test_sv2
  build/bin/test_sv2 --run_test=sv2_connman_tests
  --catch_system_error=no --log_level=test_suite

Closes #78

[enirox001]

@Sjors this is based on your suggestion in #78, would appreciate a review when you have time.

[Sjors]

Concept ACK

When looking at the commit with git show --color-moved=dimmed-zebra --color-moved-ws=ignore-space-change I noticed some comments disappeared:

(LLM's have an annoying habit of doing that, so it's always good to inspect the diff with dimmed-zebra)

[enirox001]

When looking at the commit with git show --color-moved=dimmed-zebra --color-moved-ws=ignore-space-change I noticed some comments disappeared

Thanks for catching that. i have properly restored the comments. Also recheked the diff with

  git show --color-moved=dimmed-zebra --color-moved-ws=ignore-space-change