PHP 8.4 compatibility - implicit nullable parameter deprecations in Google Analytics Reports

Problem/Motivation

When running Google Analytics Reports on PHP 8.4, deprecation warnings are triggered due to implicitly nullable parameters that are not explicitly declared as nullable.

PHP 8.4 requires parameters with a default value of NULL to use explicit nullable type hints (e.g. ?Type). Without this, PHP raises deprecation notices during execution.

These warnings affect code quality and can break strict CI pipelines that treat deprecations as failures.

Proposed resolution

Update method signatures across the module to explicitly declare nullable parameters using nullable type hints.

Remaining tasks

• ✅ File an issue
• ✅ Addition/Change/Update/Fix
• ✅ Testing to ensure no regression
• ➖ Automated unit testing coverage
• ➖ Automated functional testing coverage
• ➖ UX/UI designer responsibilities
• ➖ Readability
• ➖ Accessibility
• ➖ Performance
• ➖ Security
• ➖ Documentation
• ✅ Code review by maintainers
• ✅ Full testing and approval
• ✅ Credit contributors
• ✅ Review with the product owner
• ✅ Release notes snippet
• ✅ Release google_analytics_reports-4.0.1, google_analytics_reports-3.3.0

API changes

• N/A

Data model changes

• N/A

Release notes snippet

• fix: #3564964 PHP 8.4 compatibility - implicit nullable parameter deprecations in Google Analytics Reports