fix(cli): fix notification logic when API resource directory doesn't exist

[lazpavel]

Description of changes

• fix notification logic when API resource directory doesn't exist, for example when api is added with amplify codegen add --apiId {apiId}

Issue #9721

Description of how you validated changes

• manual testing
  -- amplify init (remove securityEnhancementNotification or init with an older API)
  -- amplify codegen add --apiId {apiId}
  -- amplify push
• yarn test
• unit tests added

Checklist

• PR description included
• yarn test passes
• Tests are changed or added
• Relevant documentation is changed or added (and PR referenced)
• New AWS SDK calls or CloudFormation actions have been added to relevant test and service IAM policies

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

[github-actions]

👋 Hi, this pull request was referenced in the v7.6.23 release!

Check out the release notes here https://github.com/aws-amplify/amplify-cli/releases/tag/v7.6.23.