feat: Update user id (#66)

[markvdouw]

• fix: Adds in new preference for userId primary identity (fix: Adds in new preference for userId primary identity #64)

• Adds preference for userId primary identity.

• Update IterableKit.kt

removed extra spaces

• Changes to remove duplicates and make it less verbose.

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Instructions

1. PR target branch should be against development
2. PR title name should follow this format: https://github.com/mParticle/mparticle-workflows/blob/main/.github/workflows/pr-title-check.yml
3. PR branch prefix should follow this format: https://github.com/mParticle/mparticle-workflows/blob/main/.github/workflows/pr-branch-check-name.yml

Summary

• {provide a thorough description of the changes}

Testing Plan

• Was this tested locally? If not, explain why.
• {explain how this has been tested, and what, if any, additional testing should be done}

Reference Issue (For mParticle employees only. Ignore if you are an outside contributor)

• Closes https://go.mparticle.com/work/REPLACEME