test(s3tables): capture weed mini stdout/stderr in catalog_spark tests

Without this, when "weed mini" fails to bind its master port within the
45s startup timeout the only diagnostic is the timeout message itself,
making flakes impossible to root-cause. The sibling catalog, catalog_dremio,
and catalog_trino packages already wire stdout/stderr through; bring
catalog_spark in line.

test/s3tables/catalog_spark/setup_test.go

@@ -121,6 +121,8 @@ func (env *TestEnvironment) StartSeaweedFS(t *testing.T) {
 		"ICEBERG_WAREHOUSE=s3://iceberg-tables",
 		"S3TABLES_DEFAULT_BUCKET=iceberg-tables",
 	)
+	env.masterProcess.Stdout = os.Stdout
+	env.masterProcess.Stderr = os.Stderr
 	if err := env.masterProcess.Start(); err != nil {
 		t.Fatalf("failed to start weed mini: %v", err)
 	}