fix(authenticator): Upgrade Amplify dependency to 2.27.0

[mattcreaser]

• PR conforms to Pull Request guidelines.

Issue #, if available:
#203

Description of changes:
Upgrade Amplify to 2.27.0 to get fix for getCurrentUser failing while offline with expired access tokens.

How did you test these changes?

• Reproduced bug

Documentation update required?

• No
• Yes (Please include a PR link for the documentation update)

General Checklist

• Added Unit Tests
• Added Integration Tests
• Security oriented best practices and standards are followed (e.g. using input sanitization, principle of least privilege, etc)
• Ensure commit message has the appropriate scope (e.g fix(liveness): message, fix(authenticator): message, fix(all): message)

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