CodeGen from PR 16763 in Azure/azure-rest-api-specs

Fix examples for some RPs (#16763)

* fix LRO_RESPONSE_HEADER error in "keyvault"

* fix LRO_RESPONSE_HEADER error in "managementgroups"

* fix XMS_EXAMPLE_NOTFOUND_ERROR error in "managementgroups"

* fix RESPONSE_BODY_NOT_IN_EXAMPLE error in "relay"

* fix XMS_EXAMPLE_NOTFOUND_ERROR error in "servicefabric"

* fix LRO_RESPONSE_HEADER error in "storage"

* update api version to 2021-06-01

* fix code style issues

Author: SDKAuto