Fix CAPIF API Events Service Test Case 5 Error Response Body

Description

The check response of "Test Case 5: Deletes an individual CAPIF Event Subscription with invalid SubscriptionId" (CAPIF Api Events Service Test Plan) expects error status 401, which is correct. But in the testplan documentation, the test case is described to expect a 404 Not Found status code.

Explanation

If SubscriptionId is invalid, it will not be found in the entries of that subscriber's certificate. This will result in the user being considered unauthorized in the validate_user.py module, which is why status code 401 Unauthorized is approriate.

Fix

Update the testplan documentation to reflect the current code implementation.