Fix 3587 regression in v0.40.0

[AndrewRTsao]

Describe the bug
It seems like v0.40.0 has introduced a regression for the fix we previously made in #3587 (to natively cast and allow support for BIGNUMERIC type). This should theoretically be separately fixed by DuckDB #9770 once the new major release of DuckDB is available but is currently customer impacting so we should still make the same fix that we made previously to resolve #3528.

Steps to Reproduce

1. Create a table in BQ that contains some BIGNUMERIC columns
2. Create a datasource in Rill Developer that reads from this BQ table (without applying a cast)

Expected Behavior: Rill Developer should be able to read this BQ datasource
Actual Behavior: Rill Developer throws an INTERNAL ERROR: Decimal has a width of 76 which is bigger than the maximum supported width of 38

Verified that it works in v0.39.1 but not v0.40.0 (pointing to the exact same BQ source). See screenshots below.