fix(localstack): corrected whitelist, test, and compose file

[kylerwsm]

Problem

In earlier PRs, we have simplified the localstack endpoint. However, the whitelist is not updated. This prevents the upload of files in development, as localstack urls are not considered valid urls. In addition, our tests and docker-compose file can also be updated or simplified.

Solution

• Corrected the whitelist url to http://localhost:4566.
• Update tests for whitelist validation to use http://localhost:4566.
• Expose only port 4566 for localstack in our compose file.