Fix CI tests

[Dhananjhay]

Proposed changes

Fix CI tests and use uv's own backend

Checklist

Put an x in the boxes that apply. You can also fill these out after creating the PR. If you are unsure about any of the choices, don't hesitate to ask!

• Changes have been tested to ensure that fix is effective or that a feature works.
• Changes pass the unit tests
• I have included necessary documentation or comments (as necessary)
• Any dependent changes have been merged and published

Notes

All PRs will undergo the unit testing before being reviewed. You may be requested to explain or make additional changes before the PR is accepted.