fix(lambda-python-alpha): use function architecture (#18696)

With this change, architecture when bundling is inferred from the target architecture of the Lambda function.

Closes #18696.

----

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

packages/@aws-cdk/aws-lambda-python-alpha/lib/function.ts

@@ -74,6 +74,8 @@ export class PythonFunction extends Function {
         entry,
         runtime,
         skip: !Stack.of(scope).bundlingRequired,
+        // define architecture based on the target architecture of the function, possibly overriden in bundling options
+        architecture: props.architecture,
         ...props.bundling,
       }),
       handler: resolvedHandler,

packages/@aws-cdk/aws-lambda-python-alpha/test/function.test.ts

@@ -1,6 +1,6 @@
 import * as path from 'path';
 import { Template } from 'aws-cdk-lib/assertions';
-import { Code, Runtime } from 'aws-cdk-lib/aws-lambda';
+import { Code, Runtime, Architecture } from 'aws-cdk-lib/aws-lambda';
 import * as lambda from 'aws-cdk-lib/aws-lambda';
 import { AssetHashType, DockerImage, Stack } from 'aws-cdk-lib';
 import { PythonFunction } from '../lib';
@@ -217,3 +217,17 @@ test('Do not skip bundling when stack requires it', () => {
 
   spy.mockRestore();
 });
+
+test('PythonFunction specifying architecture', () => {
+  new PythonFunction(stack, 'handler', {
+    entry: path.join(__dirname, 'lambda-handler'),
+    runtime: Runtime.PYTHON_3_11,
+    architecture: Architecture.ARM_64,
+  });
+
+  expect(Bundling.bundle).toHaveBeenCalledWith(
+    expect.objectContaining({
+      architecture: Architecture.ARM_64,
+    }),
+  );
+});