feat: Add Redis Sentinel support for Cache and Session handlers

[gr8man]

Description

This PR introduces support for Redis Sentinel in both Cache and Session handlers. It allows the framework to connect to a Redis Sentinel cluster to discover the current master node, enabling High Availability (HA) setups.

Key Changes:

• Cache Handlers: Added Sentinel connection logic to both PredisHandler and RedisHandler.
• Session Handler: Added Sentinel connection logic to RedisHandler in system/Session/Handlers/.
• Configuration: Updated default app/Config/Cache.php and app/Config/Session.php with examples of how to configure Sentinel endpoints and names.
• Workflows: Updated GitHub Actions (reusable-phpunit-test.yml and test-random-execution.yml) to include tests for the Redis Sentinel setup.
• Tests: Added comprehensive test coverage for PredisHandlerTest, Cache/Handlers/RedisHandlerTest, and Session/Handlers/Database/RedisHandlerTest targeting Sentinel connections.
• Code Style: Applied CS fixes and reformatted the newly added test code to ensure compliance with framework standards.

Checklists

• Wrote unit tests for new features.
• Code follows the framework's coding standards.
• Required documentation (inline/config) added.