test(logging): install app-engine-go component in env test (#4063)

Fixes broken GAE env test. 

One has to manually add `gcloud components install app-engine-go` now
diff --git a/internal/kokoro/environment.sh b/internal/kokoro/environment.sh
index 90d5018..9daccac 100755
--- a/internal/kokoro/environment.sh
+++ b/internal/kokoro/environment.sh
@@ -63,6 +63,11 @@
 export ENVCTL_ID=ci-$UUID
 echo $ENVCTL_ID
 
+# If App Engine, install app-engine-go component
+if [[ $ENVIRONMENT == *"appengine"* ]]; then
+  gcloud components install app-engine-go -q
+fi
+
 # Run the environment test for the specified GCP service
 set +e
 python3.7 -m nox --session "tests(language='go', platform='$ENVIRONMENT')"