test: update tests for v2.28.5 behavior changes (v2.28.6) (#470)

- Update n8n-version tests: 'v' prefix now supported in version strings
- Update n8n-validation tests: empty settings now return minimal defaults
  { executionOrder: 'v1' } instead of {} to avoid API rejection (Issue #431)

Conceived by Romuald Członkowski - https://www.aiadvisors.pl/en

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-authored-by: Romuald Członkowski <romualdczlonkowski@MacBook-Pro-Romuald.local>
Co-authored-by: Claude <noreply@anthropic.com>

dist/services/n8n-validation.js

@@ -106,10 +106,15 @@ function cleanWorkflowForUpdate(workflow) {
                 filteredSettings[key] = value;
             }
         }
-        cleanedWorkflow.settings = filteredSettings;
+        if (Object.keys(filteredSettings).length > 0) {
+            cleanedWorkflow.settings = filteredSettings;
+        }
+        else {
+            cleanedWorkflow.settings = { executionOrder: 'v1' };
+        }
     }
     else {
-        cleanedWorkflow.settings = {};
+        cleanedWorkflow.settings = { executionOrder: 'v1' };
     }
     return cleanedWorkflow;
 }