This commit adds a call to identify serverless cluster before fetching `/_xpack` to verify the license and supported features.
When it is serverless, the license checker uses hardcoded xpack info instead of calling xpack API. The internal pipeline of monitoring is disabled and logs error when configured to use legacy monitoring.
Fixes:
ingest-dev#2303
ingest-dev#2284
Co-authored-by: Rob Bavey <rob.bavey@elastic.co>