Fix: update documentation for CPS-2428 notification subscription APIs
Three APIs were added to manage CPS notifications:
- Create notification subscription
- Get notification subscription
- Delete notification subscription
Swagger examples were outdated and did not reflect the correct fields.
Updated documentation to ensure accurate examples for successful API execution.
- Added missing Javadoc in notification subscription class for better clarity.
Issue-ID: CPS-3094
Change-Id: I740b7721d8cfe4cea38a9da014b99989e3e13027
Signed-off-by: Arpit Singh <AS00745003@techmahindra.com>