[Enhancement] [ANCHOR: BE JAVA] Move Help Center Exception Handling to Global Exception Handler and Standardize Exception Thrown in the Help Center Feature

[Am0du]

Description
Move the exception handling logic for the Help Center feature to the global exception handler. Standardize the exceptions thrown within the Help Center feature to ensure consistent error handling across the platform.
Acceptance Criteria

• The Help Center feature should no longer contain specific exception handling logic within its classes.
• All exceptions in the Help Center feature are routed through the global exception handler.
• Standardized exception messages and statuses are used for all Help Center-related errors.
  Purpose
  To centralize exception handling, making it easier to maintain and ensure consistent error responses across the platform.
  Requirements
• Refactor the Help Center feature to remove specific exception handling logic.
• Implement standardized exceptions for all error cases within the Help Center feature.
• Ensure all exceptions are correctly handled by the global exception handler.