📝 Description

Follow-up to #9154. Refactors secret token validation by removing the standalone validate_secret_tokens function and unifying validation logic into extract_and_validate_tokens_info.

🛠️ Changes Made

• Removed redundant validate_secret_tokens function from mlrun/auth/utils.py
• Unified token validation into extract_and_validate_tokens_info with a new filter_by_authenticated_id parameter
• Updated load_and_prepare_secret_tokens to use the unified validation function
• Updated tests to reflect the refactored validation logic

✅ Checklist

• I updated the documentation (if applicable)
• I have tested the changes in this PR
• I confirmed whether my changes are covered by system tests
  • If yes, I ran all relevant system tests and ensured they passed before submitting this PR
  • I updated existing system tests and/or added new ones if needed to cover my changes
• If I introduced a deprecation:
  • I followed the Deprecation Guidelines
  • I updated the relevant Jira ticket for documentation

🧪 Testing

• Unit tests updated to cover the refactored validation logic
• Tests verify token filtering by authenticated user ID with the new filter_by_authenticated_id parameter

🔗 References

• Ticket link: N/A
• Related PR: [Auth] Enhance secret token handling with user ID filtering #9154

🚨 Breaking Changes?

• Yes (explain below)
• No

🔍️ Additional Notes

This is a code cleanup PR that consolidates duplicate validation logic introduced in #9154.