Fix Cirrus script for firebase testlab tests (#3634)

Author: stuartmorgan-g

.cirrus.yml

@@ -105,11 +105,11 @@ task:
         - export CIRRUS_COMMIT_MESSAGE=""
         - ./script/incremental_build.sh build-examples --apk
         - ./script/incremental_build.sh java-test  # must come after apk build
-        - if [[ $GCLOUD_FIREBASE_TESTLAB_KEY == ENCRYPTED* ]]; then
-        -   echo "This user does not have permission to run Firebase Test Lab tests."
-        - else
+        - if [[ -n "$GCLOUD_FIREBASE_TESTLAB_KEY" ]]; then
         -   echo $GCLOUD_FIREBASE_TESTLAB_KEY > ${HOME}/gcloud-service-key.json
         -   ./script/incremental_build.sh firebase-test-lab --device model=flame,version=29 --device model=starqlteue,version=26
+        - else
+        -   echo "This user does not have permission to run Firebase Test Lab tests."
         - fi
         - export CIRRUS_CHANGE_MESSAGE=`cat /tmp/cirrus_change_message.txt`
         - export CIRRUS_COMMIT_MESSAGE=`cat /tmp/cirrus_commit_message.txt`