fix(pgmq): run after-create script before pg_regress test

The test was failing because the pg_regress test expects the pgmq
extension to be in a fully functional state, but after pg_upgrade
the after-create script wasn't being run. This script sets up
necessary pgmq configurations that the tests depend on.

Author: yvan-sraka

nix/ext/tests/pgmq.nix

@@ -203,5 +203,8 @@ self.inputs.nixpkgs.lib.nixos.runTest {
           else:
             # Otherwise, the version should match the version from postgresql 15
             test.assert_version_matches(version)
+
+          test.run_sql_file("${../../../ansible/files/postgresql_extension_custom_scripts/pgmq/after-create.sql}")
+          test.check_pg_regress(Path("${psql_17}/lib/pgxs/src/test/regress/pg_regress"), "17", pg_regress_test_name)
     '';
 }