test: allow unused re-exports in shared test harness

The shared `tests/common` module re-exports macros and helpers that are
consumed by some but not all test binaries (e.g. reorg_test, probing_tests).
Under `-D warnings` this now fails the build with unused_imports /
unused_macros across those binaries. The module already carries
`#![allow(dead_code)]` for exactly this shared-fixture reason; extend it to
unused imports/macros so every test binary compiles again.

Author: Bartok9

tests/common/mod.rs

@@ -7,6 +7,8 @@
 
 #![cfg(any(test, cln_test, lnd_test, eclair_test, vss_test))]
 #![allow(dead_code)]
+#![allow(unused_imports)]
+#![allow(unused_macros)]
 
 pub(crate) mod external_node;
 pub(crate) mod logging;