Rename internal method to workaround false App Store flagging

[nan-li]

Description

One Line Summary

Rename an internal method setSharedInstance to setSharedOSDialogInstance due to App Store Connect rejecting builds with the previous method name.

Details

• App Store Connect is flagging our method setSharedInstance in a false negative manner
• https://github.com/OneSignal/OneSignal-iOS-SDK/pull/1374 says changing this method name they were able to successfully submit the build.

Motivation

• Fixes https://github.com/OneSignal/OneSignal-iOS-SDK/issues/1370

Scope

Just a rename of internal method, no implementation changes

Testing

Manual testing

App builds and runs

Affected code checklist

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

Checklist

Overview

• [x] I have filled out all REQUIRED sections above
• [x] PR does one thing
• [x] Any Public API changes are explained in the PR details and conform to existing APIs

Testing

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

Final pass

• [x] Code is as readable as possible.
• [x] I have reviewed this PR myself, ensuring it meets each checklist item

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