test(storage): fix copy_configuration script for stress test

[lawmicha]

Issue #

Description

For the stress test workflow, we have not yet updated this to run against amplify_outputs config. However the test exits after it copies the configuration file. The script is written in a way that it looks like either only AWSAmplifyStressTests-amplifyconfiguration.json exists or AWSS3StoragePluginTests-amplifyconfiguration.json but not both. One easy fix here is to touch the outputs file when running in the context of the stress test (when AWSAmplifyStressTests-amplifyconfiguration.json exists)

General Checklist

• Added new tests to cover change, if needed
• Build succeeds with all target using Swift Package Manager
• All unit tests pass
• All integration tests pass
• Security oriented best practices and standards are followed (e.g. using input sanitization, principle of least privilege, etc)
• Documentation update for the change if required
• PR title conforms to conventional commit style
• New or updated tests include Given When Then inline code documentation and are named accordingly testThing_condition_expectation()
• If breaking change, documentation/changelog update with migration instructions

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

[lawmicha]

storage stress tests workflow https://github.com/aws-amplify/amplify-swift/actions/runs/8840460451

storage integ tests https://github.com/aws-amplify/amplify-swift/actions/runs/8840477357