Error when unknown API endpoint is used in testserver

[shreyas-goenka]

Changes

This PR fails the acceptance test when an unknown endpoint (i.e. not stubbed) is used.

Tests

Manually:

output.txt when an endpoint is not found:

>>> [CLI] jobs create --json {"name":"abc"}
Error: No stub found for pattern: POST /api/2.1/jobs/create

How this renders in the test logs:

    --- FAIL: TestAccept/workspace/jobs/create (0.03s)
        server.go:46: 
            
            ----------------------------------------
            No stub found for pattern: POST /api/2.1/jobs/create
            
            To stub a response for this request, you can add
            the following to test.toml:
            [[Server]]
            Pattern = "POST /api/2.1/jobs/create"
            Response.Body = '''
            <response body here>
            '''
            Response.StatusCode = <response status-code here>
            ----------------------------------------

Manually checked that the debug mode still works.

[shreyas-goenka]

No longer needed