chore(integ-runner): publish integ-runner for CDK v2 (#21620)

integ-runner was published on v1, but it must have been lost in the
forward merge because it is still marked as private in v2.

This PR will enable publishing integ-runner for CDK v2.


----

### All Submissions:

* [ ] Have you followed the guidelines in our [Contributing guide?](https://github.com/aws/aws-cdk/blob/main/CONTRIBUTING.md)

### Adding new Unconventional Dependencies:

* [ ] This PR adds new unconventional dependencies following the process described [here](https://github.com/aws/aws-cdk/blob/main/CONTRIBUTING.md/#adding-new-unconventional-dependencies)

### New Features

* [ ] Have you added the new feature to an [integration test](https://github.com/aws/aws-cdk/blob/main/INTEGRATION_TESTS.md)?
	* [ ] Did you use `yarn integ` to deploy the infrastructure and generate the snapshot (i.e. `yarn integ` without `--dry-run`)?

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

packages/@aws-cdk/integ-runner/package.json

@@ -98,6 +98,5 @@
  "maturity": "experimental",
  "publishConfig": {
  "tag": "latest"
- },
- "private": true
+ }
 }

tools/@aws-cdk/pkglint/lib/rules.ts

@@ -1,6 +1,6 @@
-import { Bundle } from '@aws-cdk/node-bundle';
 import * as fs from 'fs';
 import * as path from 'path';
+import { Bundle } from '@aws-cdk/node-bundle';
 import * as caseUtils from 'case';
 import * as glob from 'glob';
 import * as semver from 'semver';
@@ -1670,6 +1670,7 @@ export class UbergenPackageVisibility extends ValidationRule {
  'awslint',
  'cdk',
  'cdk-assets',
+ '@aws-cdk/integ-runner',
  ];
 
  public validate(pkg: PackageJson): void {