Fix for on-call escalation policies endpoint

[api-clients-generation-pipeline]

See DataDog/datadog-api-spec#3774
Test branch datadog-api-spec/test/d.marin/oncall_ep

[datadog-datadog-prod-us1]

Datadog Report

All test runs 1f0d74c 🔗

❌ 5 Total Test Services: 4 Failed, 0 Passed

Test Services

Service Name	Failed	Known Flaky	New Flaky	Passed	Skipped	Total Time	Test Service View
surefirebooter12969490635568719610	3	0	0	1249	36	0s	Link
surefirebooter1356194166347833552	3	0	0	1249	36	0s	Link
surefirebooter6194535368146006604	3	0	0	1249	36	0s	Link
surefirebooter9784716958394471829	3	0	0	1249	36	0s	Link
org.codehaus.plexus.classworlds.launcher.launcher	0	0	0	0	0	4m 10.47s	Link

❌ Failed Tests (12)

This report shows up to 5 failed tests.

• Create on-call escalation policy returns "Created" response - classpath:com/datadog/api/client/v2/api/on-call.feature:On-Call

• Delete on-call escalation policy returns "No Content" response - classpath:com/datadog/api/client/v2/api/on-call.feature:On-Call

• Update on-call escalation policy returns "OK" response - classpath:com/datadog/api/client/v2/api/on-call.feature:On-Call - Details

  Expand for error

   java.lang.reflect.InvocationTargetException
  

• Create on-call escalation policy returns "Created" response - classpath:com/datadog/api/client/v2/api/on-call.feature:On-Call

• Delete on-call escalation policy returns "No Content" response - classpath:com/datadog/api/client/v2/api/on-call.feature:On-Call