SDKv3-05: Update @aws-cdk-testing/cli-integ

[TheRealAmazonKendra]

Context

The AWS SDK V2 is being deprecated. We need to remove all uses of it from the CDK.

Task Description

Remove use of sdkv2 in @aws-cdk-testing/cli-testing.

Used to make a custom client in:

• lib/aws.ts
• lib/staging/codeartifact.ts

These clients are used extensively in this package.

Considerations

There is already a test that fails silently (cdk import). Each test may need to be manually verified and updated to ensure that this doesn't occur in other places as well. Test updates may also be required.

Acceptance Criteria

1. All tests (unit and integ) pass using sdkv3.
2. No instances of sdkv2 are still in use in this package.