Description of problem:

Google cloud logging (GCP StackDriver Logs) does not support compression tuning.
Vector gcp docs

Currently compression is not set at all for GCP even if CLF specs a compression type for the output. Since GCP does not support compression, it should fail validation even if it doesn't set anything in vector.toml

Actual results:

CLF is valid but compression is not set.

Expected results:

CLF should fail validation if GCP specs compression