redfish: systems: event service: corrects RegistryPrefixes list

The list defineded in the bmcweb: Base, OpenBMC, TaskEvent
https://github.com/openbmc/bmcweb/blob/0588a3b929b2a88784db2f3dcac04d69260fb585/redfish-core/lib/event_service.hpp#L25

Signed-off-by: Joseph Liu <kwliu@nuvoton.com>
Signed-off-by: Tim Lee <timlee660101@gmail.com>
Change-Id: I22e0a5edddcb9682365fba80ccf71f66f7c40217
diff --git a/redfish/systems/eventlog/test_event_service.robot b/redfish/systems/eventlog/test_event_service.robot
index 3d4bfba..bde18fb 100644
--- a/redfish/systems/eventlog/test_event_service.robot
+++ b/redfish/systems/eventlog/test_event_service.robot
@@ -36,7 +36,7 @@
 
     ${HttpHeaders_dict}=  Create Dictionary  Content=application/json
     ${HttpHeaders_list}=  Create List  ${HttpHeaders_dict}
-    ${RegistryPrefixes_list}=  Create List  Base  OpenBMC  Task
+    ${RegistryPrefixes_list}=  Create List  Base  OpenBMC  TaskEvent
     ${ResourceTypes_list}=  Create List  Task
 
     ${payload}=  Create Dictionary