Change GA4 data API access from token to "workload identity"

[escattone]

• Request that our dev/stage GKE service accounts be given access to our GA4 stage property
• Request that our prod GKE service account be given access to our GA4 production property
• Ensure that the analyticsdata.googleapis.com service is enabled in our sumo-nonprod and sumo-prod projects within the webservices-infra repo.
• Remove the code that creates the creds from the GA_KEY
• Test that the GA4 API calls work without the GA_KEY
• Remove the GA_KEY from our dev, stage, and prod secrets