[BugFix] Fix BLS Error and API Exception Handling - Resolves #6661 and #6662

[deeleeramone]

1. Why?:

   • Resolves [Bug] Unhandled validation errors in BLS extension raise 500s on the API #6661, [Bug] BLS leaks API key to the logs if the key was not validated #6662

2. What?:

   • Sanitize the invalid API key error message from BLS.
   • Handle Field required error in the API as 422.

3. Impact:

   • Better privacy handling and improved exception handling for required fields in the API.

4. Testing Done:

Resolves #6661:

Resolves #6662: