Fix example request for expanding policyEvaluationDetails (#10203)

Co-authored-by: Jin Soon Lim <[email protected]>

Author: j5lim

specification/policyinsights/resource-manager/Microsoft.PolicyInsights/stable/2019-10-01/examples/PolicyStates_QueryResourceScopeExpandPolicyEvaluationDetails.json

@@ -3,7 +3,7 @@
     "policyStatesResource": "latest",
     "resourceId": "subscriptions/fff10b27-fff3-fff5-fff8-fffbe01e86a5/resourceGroups/myResourceGroup/providers/Microsoft.ClassicCompute/domainNames/myDomainName",
     "api-version": "2019-10-01",
-    "$expand": "policyEvaluationDetails"
+    "$expand": "PolicyEvaluationDetails"
   },
   "responses": {
     "200": {