Cannot generate external model for BigQuery information schema

[ncbkr]

We have a model that is querying the BigQuery information schema. In contrast to regular tables living in datasets within projects, the INFORMATION_SCHEMA follows a different syntax that does not have to comply with the usual <project>.<dataset>.<table> format. E.g. this would be valid identifier for an information schema table:

myProject.`region-us`.INFORMATION_SCHEMA.TABLES` 

We have a query like the following:

SELECT *
FROM `region-eu`.INFORMATION_SCHEMA.JOBS

When running sqlmesh create_external_models, we receive the following warning

2024-10-31 15:08:10,605 - ThreadPoolExecutor-0_0 - sqlmesh.core.schema_loader - WARNING - Unable to get schema for '"region-eu"."INFORMATION_SCHEMA"."JOBS"': '404 GET https://bigquery.googleapis.com/bigquery/v2/projects/region-eu/datasets/INFORMATION_SCHEMA/tables/JOBS?prettyPrint=false: Project region-eu is not found. Make sure it references valid GCP project that hasn't been deleted.; Project id: region-eu'. (schema_loader.py:62)

The warning indicates that SQLMesh is interpreting region-eu as the project name, which is not true for information schema tables.