Improvement: DO-3914 replace deprecated shortid with nanoid

[krzysztof-causalens]

Motivation and Context

shortid has been deprecated for a while. We've been slowly migrating to nanoid, this PR removes remaining references to shortid and moves all of them over to nanoid.

Implementation Description

Any new dependencies Introduced

How Has This Been Tested?

Tests passing

PR Checklist:

• I have implemented all requirements? (see JIRA, project documentation).
• I am not affecting someone else's work, If I am, they are included as a reviewer.
• I have added relevant tests (unit, integration or regression).
• I have added comments to all the bits that are hard to follow.
• I have added/updated Documentation.
• I have updated the appropriate changelog with a line for my changes.

Screenshots (if appropriate):

[patricia-causalens]

Thank you for doing this!