Google-bigquery cover authentication options with tests

When google-bigquery test coverage was improved (see [ticket](https://github.com/apache/camel-quarkus/issues/3949)), several authentication configurations without coverage were discovered.

There is a similar [ticket](https://github.com/apache/camel-quarkus/issues/new) for google-pubsub. It should be enough to cover authentication on one component only (need to be verified). Google-bigquery tests use wiremock, therefore it might be easier to cover several authentication approaches easily with google-bigquery. It's worth the investigation.