fix: constrain setup tools version to fix broken build

[rohan-chaturvedi]

🔍 Overview

A recent update to setuptools which remove the test command causes autobahn to fail installs:

pypa/setuptools#4519
crossbario/autobahn-python#1644

💡 Proposed Changes

Constrain setuptools to version <72 to allow autobahn to install correctly.

• Added a constraints.txt file
• Updated the backend Dockerfile to use the contraints.txt file when running pip install

📝 Release Notes

Fixed a broken dependency issue with setuptools and autobahn

💚 Did You...

• Ensure linting passes (code style checks)?
• Update dependencies and lockfiles (if required)
  - [ ] Regenerate graphql schema and types (if required)
• Verify the app builds locally?
• Manually test the changes on different browsers/devices?