fix: Address Edge Case Upgrade Crash

[BrandonStalnaker]

Summary

• When upgrading from 8.0.6 to 8.5.1 (which was Branch: 1.45.2 to Branch: 3.10.0) the branchKey would de-initialize before it was used in the async block.

Testing Plan

• Was this tested locally? Yes
• Tested using simulator and confirmed data flowing to the Branchmetrics Kit

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

• Closes https://go.mparticle.com/work/SQDSDKS-7340

[rmi22186]

in the PR description, can you just state the explicit scenario we are aware of?