[Model Monitoring] Remove v3io from mlrun config, remove deprecated MM ENDPOINT_STORE_CONNECTION

[royischoss]

This change is part of https://iguazio.atlassian.net/browse/CEML-358 , https://iguazio.atlassian.net/browse/CEML-229
Includes:

1. Adding MLRUN_MODEL_ENDPOINT_MONITORING__STORE_PREFIXES__USER_SPACE, MLRUN_MODEL_ENDPOINT_MONITORING__STORE_PREFIXES__MONITORING_APPLICATION to override mlrun defualt config to remove v3io definitions.
2. Remove MLRUN_MODEL_ENDPOINT_MONITORING__ENDPOINT_STORE_CONNECTION that was deprecated.

No breaking changes, Model monitoring works with/without this change

[Copilot]

Pull request overview

This PR removes deprecated v3io-related configuration from MLRun model monitoring and introduces new S3-based store prefix configurations. The changes align with the broader initiative (CEML-358, CEML-229) to migrate away from v3io storage and establish explicit S3 paths for model monitoring data.

Changes:

• Added two new model monitoring store prefix configurations: USER_SPACE and MONITORING_APPLICATION pointing to S3 paths
• Removed deprecated ENDPOINT_STORE_CONNECTION configuration that referenced a DSN template

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.