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

[Am0du]

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

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