SPINEL_PROP_SRP_CLIENT_SERVICE_KEY_ENABLED value

SRP Client Service Key Inclusion Enabled Format `b` : Read-Write Required capability: `SPINEL_CAP_SRP_CLIENT` & `SPINEL_CAP_REFERENCE_DEVICE`. This boolean property indicates whether the "service key record inclusion" mode is enabled or not. When enabled, SRP client will include KEY record in Service Description Instructions in the SRP update messages that it sends. KEY record is optional in Service Description Instruction (it is required and always included in the Host Description Instruction). The default behavior of SRP client is to not include it. This function is intended to override the default behavior for testing only.