fix(conformance): block-style chainsaw checks (flow-map broke on contains comma)

My previous commit converted =~ to contains() but kept flow style
'check: { (contains($stdout, 'X')): true }' — the comma inside contains() is a
YAML flow-map separator, so 9 tests failed yamllint ('expected , or }'). Convert
those checks to block style (matching data-survival), where a comma in the key
scalar is fine. Gate PASS; data-survival still green.

Co-Authored-By: Claude Opus 4.8 (1M context) <[email protected]>

conformance/tests/l3-fault-injection/gitops-drift/chainsaw-test.yaml

@@ -45,7 +45,8 @@ spec:
               set -euo pipefail
               echo "TODO: within Flux interval, assert live value == git-declared value"
               echo "DRIFT_REVERTED_OK"
-            check: { (contains($stdout, 'DRIFT_REVERTED_OK')): true }
+            check:
+              (contains($stdout, 'DRIFT_REVERTED_OK')): true
       finally:
         - script:
             content: 'echo "TODO: ensure resource left in git-declared state"'