[Feature Request]: Support query parameter in read_gbq

### What would you like to happen?

Currently read_gbq can only read an entire table, we should also allow specifying the query parameter, which behaves the same as the query parameter in BigQueryIO and in pandas read_gbq.

Part of #20810

### Issue Priority

Priority: 2

### Issue Component

Component: dsl-dataframe

Start by locating the read_gbq entry point in the dsl-dataframe component and compare its current table-reading behavior with BigQueryIO and pandas read_gbq. Review issue #20810 for related context. Done means read_gbq accepts a query parameter and its behavior matches those existing interfaces, with coverage for query-based reads.

Written by the indexing model from the issue text.