substrate/zombienet: Fix 0002-validators-warp-sync (paritytech#6379)

This PR fixes the `0002-validators-warp-sync` zombienet test by matching
for a specific error case.

The following PR introduced a new error for validators that don't have
public addresses available for publishing in the DHT:
- paritytech#6298
The log line was moved from `eprintln!("Warning: ...` in sc-cli to the
authority discovery where it is printed properly as an error.


cc @paritytech/sdk-node

Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io>

substrate/zombienet/0002-validators-warp-sync/test-validators-warp-sync.zndsl

@@ -35,7 +35,10 @@ bob: reports block height is at least {{DB_BLOCK_HEIGHT}} within 10 seconds
 alice: reports substrate_beefy_best_block is at least {{200*180/6}} within 180 seconds
 bob: reports substrate_beefy_best_block is at least {{200*180/6}} within 180 seconds
 
-alice: count of log lines containing "error" is 0 within 10 seconds
+# Validators started without public addresses must emit an error.
+# Double check the error is the expected one.
+alice: log line matches "No public addresses configured and no global listen addresses found" within 60 seconds
+alice: count of log lines containing "error" is 1 within 10 seconds
 bob: count of log lines containing "verification failed" is 0 within 10 seconds
 
 # new blocks were built