ci: integrate client bundlesize observability script
Created by: valerybugakov
Context
Integrate the bundlesize upload script into the CI pipeline to enable continuous bundlesize monitoring.
The Honeycomb client env API key secret was added here https://github.com/sourcegraph/infrastructure/pull/3740. Closes https://github.com/sourcegraph/sourcegraph/issues/39737.
Test plan
Check if bundlesize stats are uploaded to Honeycomb during the Web Enterprise build
step.
See dashboard here.
App preview:
Check out the client app preview documentation to learn more.