feat(lambda): add Python 3.14 runtime for Lambda (#35869)

### Issue # (if applicable)

N/A

### Reason for this change



Add Python 3.14 Runtime to the available [Lambda Runtimes constants](https://docs.aws.amazon.com/cdk/api/v2/docs/aws-cdk-lib.aws_lambda.Runtime.html#initializer)

### Description of changes



Have added integration tests to validate the runtime support

### Describe any new or updated permissions being added



No

### Description of how you validated changes



### 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: bnusunny

packages/@aws-cdk-testing/framework-integ/test/aws-lambda/test/integ.runtime.inlinecode.js.snapshot/aws-cdk-lambda-runtime-inlinecode.assets.json

@@ -250,6 +250,56 @@
     "PYTHON313ServiceRole907582AC"
    ]
   },
+  "PYTHON314ServiceRoleB0324A64": {
+   "Type": "AWS::IAM::Role",
+   "Properties": {
+    "AssumeRolePolicyDocument": {
+     "Statement": [
+      {
+       "Action": "sts:AssumeRole",
+       "Effect": "Allow",
+       "Principal": {
+        "Service": "lambda.amazonaws.com"
+       }
+      }
+     ],
+     "Version": "2012-10-17"
+    },
+    "ManagedPolicyArns": [
+     {
+      "Fn::Join": [
+       "",
+       [
+        "arn:",
+        {
+         "Ref": "AWS::Partition"
+        },
+        ":iam::aws:policy/service-role/AWSLambdaBasicExecutionRole"
+       ]
+      ]
+     }
+    ]
+   }
+  },
+  "PYTHON314C98D0951": {
+   "Type": "AWS::Lambda::Function",
+   "Properties": {
+    "Code": {
+     "ZipFile": "def handler(event, context):\n  return \"success\""
+    },
+    "Handler": "index.handler",
+    "Role": {
+     "Fn::GetAtt": [
+      "PYTHON314ServiceRoleB0324A64",
+      "Arn"
+     ]
+    },
+    "Runtime": "python3.14"
+   },
+   "DependsOn": [
+    "PYTHON314ServiceRoleB0324A64"
+   ]
+  },
   "NODEJS20XServiceRole188A4E38": {
    "Type": "AWS::IAM::Role",
    "Properties": {
@@ -377,6 +427,11 @@
     "Ref": "PYTHON3136F4F65AE"
    }
   },
+  "PYTHON314functionName": {
+   "Value": {
+    "Ref": "PYTHON314C98D0951"
+   }
+  },
   "NODEJS20XfunctionName": {
    "Value": {
     "Ref": "NODEJS20X70A25ADE"