chore(custom-resources): update python runtime for custom resources (#31166)

### Issue # (if applicable)

Closes #31245

### Reason for this change

Support latest python runtime that's available everywhere

### Description of changes

Update custom resource handler runtime to python 3.11

### Description of how you validated changes

There were initially 40+ failed integration tests due to this change, all these tests are re-ran by deploying and verifying (no `dry-run` flag used). Now all existing tests are passing.  

### Checklist
- [x] My code adheres to the [CONTRIBUTING GUIDE](https://github.com/aws/aws-cdk/blob/main/CONTRIBUTING.md) and [DESIGN GUIDELINES](https://github.com/aws/aws-cdk/blob/main/docs/DESIGN_GUIDELINES.md)

----

*By submitting this pull request, I confirm that my contribution is made under the terms of the Apache-2.0 license*

Author: GavinZZ

packages/@aws-cdk-testing/framework-integ/test/aws-appconfig/test/integ.configuration.js.snapshot/appconfigconfigurationDefaultTestDeployAssert6752CD38.assets.json

@@ -936,7 +936,7 @@
       "Arn"
      ]
     },
-    "Runtime": "python3.9",
+    "Runtime": "python3.11",
     "Timeout": 900
    },
    "DependsOn": [