Support R windows_amd64_rtools build

[natbprice]

It appears that the azure extension does not currently work with R on Windows because it requires a special build (GCC 12/MinGW-w64). See https://github.com/duckdb/duckdb/pull/10204 and https://github.com/duckdb/duckdb-r/issues/100.

There is a workflow for this build, but it appears that it is being excluded in https://github.com/duckdb/duckdb_azure/blob/main/.github/workflows/MainDistributionPipeline.yml. I assume this is because it does not work as-is, but it is a bit beyond my understanding to determine what might be required to fix this issue.