Fix: Prevent crash with nil HTTPResponse headers

[jennantilla]

Description

One Line Summary

Prevent crash with nil HTTPResponse headers by adding fallback to empty dictionary.

Details

This PR addresses customer-reported issues regarding the NSInvalidArgumentException crash [1] [2].

Changes made in Release 5.2.6 introduced response headers getting stored in a dictionary. However, when these headers are nil (for example, due to no internet connection), the request is never actually made, leading to the reported crash.

This PR prevents the crash by adding a fallback to an empty dictionary.

Scope

Changes are limited to the handleJSONNSURLResponse method.

Testing

Manual testing

Tested turning off wifi on an iPhone 16 Pro simulator running iOS 18.0. With the changes in this PR, the crash is prevented.

Affected code checklist

• Notifications
  • Display
  • Open
  • Push Processing
  • Confirm Deliveries
• Outcomes
• Sessions
• In-App Messaging
• REST API requests
• Public API changes

Checklist

Overview

• I have filled out all REQUIRED sections above
• PR does one thing
  • If it is hard to explain how any codes changes are related to each other then it most likely needs to be more than one PR
• Any Public API changes are explained in the PR details and conform to existing APIs

Testing

• I have included test coverage for these changes, or explained why they are not needed
• All automated tests pass, or I explained why that is not possible
• I have personally tested this on my device, or explained why that is not possible

Final pass

• Code is as readable as possible.
  • Simplify with less code, followed by splitting up code into well named functions and variables, followed by adding comments to the code.
• I have reviewed this PR myself, ensuring it meets each checklist item
  • WIP (Work In Progress) is ok, but explain what is still in progress and what you would like feedback on. Start the PR title with "WIP" to indicate this.

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