test: fix expected SubType for wait_for_callback in tests (#9097)

Expect `WaitForCallback` instead of `RunInChildContext`

Author: valerena

tests/integration/testdata/durable/functions/wait_for_callback/expected_history.json

@@ -12,7 +12,7 @@
   },
   {
     "EventType": "ContextStarted",
-    "SubType": "RunInChildContext",
+    "SubType": "WaitForCallback",
     "EventId": 2,
     "Name": "external_call",
     "ContextStartedDetails": {}
@@ -60,7 +60,7 @@
   },
   {
     "EventType": "ContextSucceeded",
-    "SubType": "RunInChildContext",
+    "SubType": "WaitForCallback",
     "EventId": 8,
     "Name": "external_call",
     "ContextSucceededDetails": {

tests/integration/testdata/durable/functions/wait_for_callback/expected_history_failure.json

@@ -12,7 +12,7 @@
   },
   {
     "EventType": "ContextStarted",
-    "SubType": "RunInChildContext",
+    "SubType": "WaitForCallback",
     "EventId": 2,
     "Name": "external_call",
     "ContextStartedDetails": {}
@@ -60,7 +60,7 @@
   },
   {
     "EventType": "ContextFailed",
-    "SubType": "RunInChildContext",
+    "SubType": "WaitForCallback",
     "EventId": 8,
     "Name": "external_call",
     "ContextFailedDetails": {