StackSet asset deployment dependency not correctly set in construct

[cgatt]

If the StackSet and StackSetStack are nested in a construct, the StackSet will not have a dependency set on the AssetBucketDeployment, as the StackSetStack places the deployment in the scope of its parent stack, but the StackSet checks for the children of its current scope: https://github.com/cdklabs/cdk-stacksets/blob/main/src/stackset.ts#L662-L666
Minimal Reproduction:

import { App, Stack } from 'aws-cdk-lib';
import { Code, Function, Runtime } from 'aws-cdk-lib/aws-lambda';
import { Bucket } from 'aws-cdk-lib/aws-s3';
import { StackSet, StackSetStack, StackSetTarget, StackSetTemplate } from 'cdk-stacksets';
import { Construct } from 'constructs';


const app = new App();
const stack = new Stack(app, 'ParentStack');

const construct = new Construct(stack, 'Construct');

const assetBucket = new Bucket(construct, 'AssetBucket', { bucketName: 'prefix-us-east-1' });

const stackSetStack = new StackSetStack(construct, 'StackSetStack', {
  assetBuckets: [assetBucket],
  assetBucketPrefix: 'prefix',
});

new Function(stackSetStack, 'TestLambda', {
  code: Code.fromAsset('path/to/lambda/code'),
  handler: 'index.handler',
  runtime: Runtime.NODEJS_20_X,
});

new StackSet(construct, 'MyStackSet', {
  target: StackSetTarget.fromOrganizationalUnits({
    regions: ['us-east-1'],
    organizationalUnits: ['ou-abc123'],
  }),
  template: StackSetTemplate.fromStackSetStack(stackSetStack),
});

app.synth();

Potential Fix:

for (const fileAssetResourceName of cdkStacksets.fileAssetResourceNames) {
  const fileAssetResource = Stack.of(this).node.tryFindChild(fileAssetResourceName);
  fileAssetResource && this.node.addDependency(fileAssetResource);
}

Though it is probably better to pass a reference to the AssetBucketDeployment instead of relying on assumptions about the construct tree.