refactor(bigquery): return data_project as database, not dataset_id

BREAKING CHANGE: the bigquery `current_database` method returns the `data_project` instead of the `dataset_id`. Use `current_schema` to retrieve `dataset_id`.  To explicitly list tables in a given project and dataset, you can use `f"{con.current_database}.{con.current_schema}"`

ibis/backends/bigquery/__init__.py

@@ -7,7 +7,6 @@
 import glob
 import os
 import re
-import warnings
 from functools import partial
 from typing import TYPE_CHECKING, Any, Callable, Optional
 from urllib.parse import parse_qs, urlparse
@@ -654,13 +653,7 @@ def raw_sql(self, query: str, results=False, params=None):
 
     @property
     def current_database(self) -> str:
-        warnings.warn(
-            "current_database will return the current *data project* in ibis 7.0.0; "
-            "use current_schema for the current BigQuery dataset",
-            category=FutureWarning,
-        )
-        # TODO: return self.data_project in ibis 7.0.0
-        return self.dataset
+        return self.data_project
 
     @property
     def current_schema(self) -> str | None: