feat: add custom events support

[fadi-george]

Description

One Line Summary

• adds custom events logic to the unity sdk

Details

• updates unity example behavior script to now include trackEvent test example with complex properties
• updates unity scene to have trackEvent button under login button for easy testing
• updates AndroidUserManager to expose TrackEvent
• updates AndroidJavaObjectExtentions to have a toMap override to handle Dictionary<string, object>
• Updates ios dependency (OneSignaliOSDependencies.xml) to use 5.4
• Updates android depedency (AndroidResolverDependencies) to use 5.6.1
• Updates OneSignalUnityBridgeUser and iOUSUserManager to expose track event call from ios sdk

Dashboard logs:

Track event button:

Motivation

We want to allow using custom events for more platforms / sdks.

Scope

Adds a new method for the user namespace. Also updates the required android/ios versions.

Testing

Manual testing

Tested on ios and android emulators by switching build profiles and running them. See screenshots above.

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 

[claude]

Code review

No issues found. Checked for bugs and CLAUDE.md compliance.