Backport v2023 <- v2025dev2: Save connman config before running tests

Since connman tests modify the network settings save the config and restore it after the tests. This ensures that the right configuration is applied and network is available.

This causes issues in tests running on QEMU which failed after running connman tests due to DNS server not reachable.

Signed-off-by: Walter Lozano walter.lozano@collabora.com