feat: Add custom event logging for selectplacements

[Mansi-mParticle]

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

• Added a custom selectplacements event that is logged when selectPlacement is called.
  The attributes passed to selectPlacement are added as custom attributes to the MPEvent, which is logged using EventType.Other.

Testing Plan

• Was this tested locally? If not, explain why.
• Tested the feature in the sample app and added a unit test for validation.

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

• Closes Ticket

[rmi22186]

There may be value is separating custom attributes to show what a developer passed in vs what we add to the ultimate selectPlacements call. I am meeting with the GTM team to discuss and will follow up.