add length check to avoid panic

add length check to match linux_web_app to avoid potential panic in windows_web_app

linux change done in hashicorp#21328

internal/services/appservice/helpers/auto_heal.go

@@ -401,7 +401,17 @@ func expandAutoHealSettingsWindows(autoHealSettings []AutoHealSettingWindows) *w
 	}
 
 	autoHeal := autoHealSettings[0]
+
+	if len(autoHeal.actions) > 0 {
+		action := autoHeal.Actions[0]
+		result.Actions.ActionType = web.AutoHealActionType(action.ActionType)
+		result.Actions.MinProcessExecutionTime = pointer.To(action.MinimumProcessTime)
+	}
 
+	if len(autoHeal.Triggers) == 0 {
+		return result
+	}
+
 	triggers := autoHeal.Triggers[0]
 	if len(triggers.Requests) == 1 {
 		result.Triggers.Requests = &web.RequestsBasedTrigger{
@@ -462,10 +472,7 @@ func expandAutoHealSettingsWindows(autoHealSettings []AutoHealSettingWindows) *w
 		result.Triggers.StatusCodes = &statusCodeTriggers
 		result.Triggers.StatusCodesRange = &statusCodeRangeTriggers
 	}
-
-	action := autoHeal.Actions[0]
-	result.Actions.ActionType = web.AutoHealActionType(action.ActionType)
-	result.Actions.MinProcessExecutionTime = pointer.To(action.MinimumProcessTime)
+
 	if len(action.CustomAction) != 0 {
 		customAction := action.CustomAction[0]
 		result.Actions.CustomAction = &web.AutoHealCustomAction{