Use Forward Target Swizzling check for UNUserNotificationCenterDelegate methods

[emawby]

Description

One Line Summary

Use the new Swizzling Forwarder class to check for forwardingSelectors when looking for original implementors of UNUserNotificationCenterDelegate methods.

Details

PR #1091 Adding the SwizzlingForwarder class that checks to see if there is a forwardingTarget for selectors when trying to call original implementations of our swizzled methods. That PR added the behavior for AppDelegate methods but not for UNUserNotificationCenterDelegate methods. This PR adds the behavior for UNUserNotificationCenterDelegate methods.

Motivation

Apps or other frameworks could be using forwardingTargets for UNUserNotificationCenterDelegate methods, and with our current swizzling implementation we would not properly forward those calls on.

Scope

iOS SDK method swizzling

Testing

Unit testing

Added unit tests for the forwarding targets, infinite loop test, and existing selectors

Manual testing

tested on my iOS device

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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This change is 

[jkasten2]

Reviewed 2 of 2 files at r1, all commit messages.
Reviewable status: complete! all files reviewed, all discussions resolved (waiting on @nan-li)