fix: Correct mixed language issue for spm

[BrandonStalnaker]

Summary

• SPM could not integrate our latest version because we included Swift code along with the Objective-C code. This was not an issue when integrating with cocoaPods. To solve this problem we either needed to split the code into two language dependent targets or ship the framework as an xcframework binary. Since it was simpler and using binaries causes the SDK to be. harder to test I went with the first option

Testing Plan

• Was this tested locally? If not, explain why.
• Confirmed all unit tests and that the project file, package.swift file, and pod lib lint all run successfully. I also succesfully integrated the kit into swift and objective-c projects using SPM and cocoapods respectively.

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

• Closes https://go.mparticle.com/work/SQDSDKS-7584