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
• New 5.1.0 #1374 says changing this method name they were able to successfully submit the build.

Motivation

• Fixes [Bug]: Asset validation failed (50) The app references non-public selectors in Payload/Runner.app/Frameworks/OneSignalFramework.framework/OneSignalFramework: setSharedInstance #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

• I have filled out all REQUIRED sections above
• PR does one thing
• 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.
• I have reviewed this PR myself, ensuring it meets each checklist item

---

This change is