outputs.stackdriver - Scope Quota Costs to the Destination Google Project instead of SA Project

[crflanigan]

Use Case

Currently, the Google Project associated with the Service Account used to send metrics to GMP is the one that is charged for ingestion. This creates an issue when using multiple instances of outputs.stackdriver to send metrics to different projects, as all ingestion costs are charged to the Service Account’s project instead of the respective destination projects.

Expected behavior

When using multiple outputs.stackdriver configurations in Telegraf, the quota costs for metric ingestion should be attributed to the specific project defined in each configuration instead of defaulting to the service account’s project.

Actual behavior

All ingestion is charged to the Google Service Account's project that is used to send the metrics, not the project where the metrics are actually being stored in.

Additional info

I have created a PR to address this issue here:
#16583