[VC-43403] CyberArk(identity): enhance test logging and context handling

[wallrj-cyberark]

Some things I forgot to commit to #698 :

• Integrated klog for improved logging in identity tests
• Updated MockIdentityServer to use testing.TB for broader compatibility
• Added request logging in mockIdentityServer.ServeHTTP for better debugging

Testing

The extra logging helps understand what's going on if and when the tests fail:

$ go test ./pkg/internal/cyberark/identity/... -v -args -testing.v 6
=== RUN   Test_IdentityAdvanceAuthentication
=== RUN   Test_IdentityAdvanceAuthentication/persistent_login_not_set
    mock.go:75: POST /Security/AdvanceAuthentication
    round_trippers.go:632: I0827 17:12:58.518756] Response verb="POST" url="https://127.0.0.1:46037/Security/AdvanceAuthentication" status="403 Forbidden" milliseconds=3
=== RUN   Test_IdentityAdvanceAuthentication/success
    mock.go:75: POST /Security/AdvanceAuthentication
    round_trippers.go:632: I0827 17:12:58.522964] Response verb="POST" url="https://127.0.0.1:43719/Security/AdvanceAuthentication" status="200 OK" milliseconds=2
    identity.go:419: I0827 17:12:58.523056] successfully completed AdvanceAuthentication request to CyberArk Identity; login complete username="test@example.com"
=== RUN   Test_IdentityAdvanceAuthentication/incorrect_password
    mock.go:75: POST /Security/AdvanceAuthentication
    round_trippers.go:632: I0827 17:12:58.525780] Response verb="POST" url="https://127.0.0.1:44419/Security/AdvanceAuthentication" status="200 OK" milliseconds=2
=== RUN   Test_IdentityAdvanceAuthentication/bad_action
    mock.go:75: POST /Security/AdvanceAuthentication
    round_trippers.go:632: I0827 17:12:58.530060] Response verb="POST" url="https://127.0.0.1:46513/Security/AdvanceAuthentication" status="200 OK" milliseconds=3
=== RUN   Test_IdentityAdvanceAuthentication/bad_mechanism_id
    mock.go:75: POST /Security/AdvanceAuthentication
    round_trippers.go:632: I0827 17:12:58.534118] Response verb="POST" url="https://127.0.0.1:36853/Security/AdvanceAuthentication" status="200 OK" milliseconds=2
=== RUN   Test_IdentityAdvanceAuthentication/bad_session_id
    mock.go:75: POST /Security/AdvanceAuthentication
    round_trippers.go:632: I0827 17:12:58.538477] Response verb="POST" url="https://127.0.0.1:33319/Security/AdvanceAuthentication" status="200 OK" milliseconds=3
--- PASS: Test_IdentityAdvanceAuthentication (0.02s)
    --- PASS: Test_IdentityAdvanceAuthentication/persistent_login_not_set (0.01s)
    --- PASS: Test_IdentityAdvanceAuthentication/success (0.00s)
    --- PASS: Test_IdentityAdvanceAuthentication/incorrect_password (0.00s)
    --- PASS: Test_IdentityAdvanceAuthentication/bad_action (0.01s)
    --- PASS: Test_IdentityAdvanceAuthentication/bad_mechanism_id (0.00s)
    --- PASS: Test_IdentityAdvanceAuthentication/bad_session_id (0.00s)
=== RUN   Test_IdentityStartAuthentication
=== RUN   Test_IdentityStartAuthentication/successful_request
    mock.go:75: POST /Security/StartAuthentication
=== RUN   Test_IdentityStartAuthentication/successful_request,_multiple_challenges
    mock.go:75: POST /Security/StartAuthentication
=== RUN   Test_IdentityStartAuthentication/successful_request,_multiple_mechanisms
    mock.go:75: POST /Security/StartAuthentication
=== RUN   Test_IdentityStartAuthentication/successful_request,_no_username_/_password_(UP)_mechanism_available
    mock.go:75: POST /Security/StartAuthentication
=== RUN   Test_IdentityStartAuthentication/failed_request
    mock.go:75: POST /Security/StartAuthentication
--- PASS: Test_IdentityStartAuthentication (0.02s)
    --- PASS: Test_IdentityStartAuthentication/successful_request (0.00s)
    --- PASS: Test_IdentityStartAuthentication/successful_request,_multiple_challenges (0.00s)
    --- PASS: Test_IdentityStartAuthentication/successful_request,_multiple_mechanisms (0.00s)
    --- PASS: Test_IdentityStartAuthentication/successful_request,_no_username_/_password_(UP)_mechanism_available (0.00s)
    --- PASS: Test_IdentityStartAuthentication/failed_request (0.00s)
PASS
ok      github.com/jetstack/preflight/pkg/internal/cyberark/identity    0.054s
?       github.com/jetstack/preflight/pkg/internal/cyberark/identity/cmd/testidentity   [no test files]