DodoApp: Use untrusted-external runtime class for app runner

Change-Id: I6beab523e1688fc98c2b6a5b756f46a5fc89f3cb
diff --git a/charts/app-runner/values.yaml b/charts/app-runner/values.yaml
index 1d21e06..afc9481 100644
--- a/charts/app-runner/values.yaml
+++ b/charts/app-runner/values.yaml
@@ -10,3 +10,4 @@
 appPort: 8080
 managerAddr: ""
 volumes: []
+runtimeClassName: ""