Add empty string check to region value from matchmaking results

[FelixWentworth-Unity]

explicitly check for null or empty, as tickets without QoS may pass empty Region string value

Add tests to validate when Region is "" in matchmaking results

Pull Request

Description

Type of Change

• Bug fix (non-breaking change that fixes an issue)
• New feature (non-breaking change that adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation update
• Security fix
• Performance improvement

Provider Integration

• GameLift
• Multiplay
• PlayFab
• Multiplay by Rocket Science
• New Provider Integration
• General/Infrastructure
• Documentation

Changes Made

• Added explicit check to Region value IsNullOrEmpty to fallback to default region correctly when the matchmaker cannot pick a region from QoS data on tickes

Testing

• Tested locally
• Tested with actual provider integration
• Added/updated unit tests
• Verified no breaking changes

Security Checklist

• No credentials, API keys, or secrets committed
• Ran secret scan before committing
• Reviewed all changes for sensitive data
• Updated .gitignore if needed
• Followed security best practices from SECURITY.md

Code Provenance

• All code is original work created by me
• I have the right to submit this code under the Unity Companion License
• I did not copy code verbatim from provider documentation without attribution
• No proprietary or confidential code is included
• All third-party code is properly attributed and licensed

License Agreement

• I agree to license my contributions under the Unity Companion License
• I understand that Unity retains all rights to contributed code as specified in the license
• I have read and agree to the terms in CONTRIBUTING.md

Documentation

• Updated README.md if needed
• Updated CONFIGURATION.md for affected modules
• Added/updated code comments
• No documentation changes needed

Provider Terms Compliance

• Changes do not violate provider terms of service
• Changes do not encourage violation of rate limits or usage policies
• Provider names used descriptively without implying endorsement
• No provider logos or branding materials added

Additional Notes

Community Support Acknowledgment

• I understand this is a community-driven project
• I understand reviews are conducted on a best-effort basis
• I am willing to address review feedback