feat: Add IterableAppExtensions module to SPM support

[mmustafa-tse]

Summary

• A customer is not able to utilize the IterableAppExtensions module since we don’t include it in our package.swift which is causing errors on compile when they install the Iterable kit via SPM

Testing Plan

• Was this tested locally? If not, explain why.
• E2E tested

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

• Closes https://go.mparticle.com/work/SQDSDKS-7217

[BrandonStalnaker]

LGTM