fix(ci): use the entrypoint.sh to change the Network

.github/workflows/ci-unit-tests-docker.yml

@@ -301,6 +301,7 @@ jobs:
           echo "An error occurred while processing the logs.";
           exit 1;
         env:
+          ZEBRA_CONF_PATH: '/etc/zebrad/zebrad.toml'
           NETWORK: Testnet
 
   # Test that Zebra works using the $ZEBRA_CONF_PATH config