Add variable for slurm UID in omnia-install

[heyealex]

Submission Checklist

• Have you installed and run this change against pre-commit? (pre-commit install)
• Are all tests passing? (make tests)
• Have you written unit tests to cover this change?
• Is unit test coverage still above 80%?
• Have you updated all applicable documentation?
• Have you followed the guidelines in our Contributing document?

[heyealex]

Had to push a fix, so the initial review got dismissed. Tested locally and in the integration tests and all is working now.