chore: remove AWS CodeBuild workflows

[MikeMcC399]

Issue

• Referring to issue AWS CodeBuild Cypress Cloud example stopped running in July 2023 cypress-documentation#5538 and response AWS CodeBuild Cypress Cloud example stopped running in July 2023 cypress-documentation#5538 (comment)

We don't intend to continue supporting running the AWS CodeBuild

The AWS CodeBuild workflows are obsolete.

Change

Remove the unused and outdated files:

• https://github.com/cypress-io/cypress-realworld-app/blob/develop/buildspec.yml
• https://github.com/cypress-io/cypress-realworld-app/blob/develop/buildspec-types-unit.yml

[cypress-app-bot]

• Create a Draft Pull Request if your PR is not ready for review. Mark the PR as Ready for Review when you're ready for a Cypress team member to review the PR.

[MikeMcC399]

Encountered some network flake (HTTP 502 Gateway error) and test flake from yarn test:unit:ci
After two force pushes with no changes, CI tests are successful! 🙂