feat: add google experiment env vars for image (#3257)

Co-authored-by: Subir Jolly <subirjolly@Subirs-MacBook-Pro.local>

Author: subirjolly

docker/Dockerfile.chronograf

@@ -25,6 +25,8 @@ ENV UI_SHA=local_dev_mode
 # Global Search ENV vars
 ENV GLOBALSEARCH_API_KEY=
 ENV GLOBALSEARCH_APP_ID=
+# Google Experiments ENV vars
+ENV PAYG_CREDIT_EXPERIMENT_ID=
 
 # This is the origin of the URL needed to access the running container (optional)
 # ENV PUBLIC=http://foobar

docker/Dockerfile.chronograf.prod

@@ -36,6 +36,8 @@ ARG RUDDERSTACK_WRITE_KEY
 ARG GLOBALSEARCH_API_KEY
 # Global Search App ID
 ARG GLOBALSEARCH_APP_ID
+# Google Experiment ID for PAYG $250 Credit
+ARG PAYG_CREDIT_EXPERIMENT_ID
 
 COPY . /repo/ui
 WORKDIR /repo/ui