TST: Use indices fixture in tests/indexes/test_base.py (#32963)

* [#30914] Make a code check which bans imports of fixtures in tests

* using indices fixture instead of duplicative index fixture

* calling 'indices' fixture as 'index'

* Revert "calling 'indices' fixture as 'index'"

This reverts commit 1eba26d.

* using string_index fixture instead of @pytest.mark.parametrize(indices, [string], indirect=True)

* Revert "using string_index fixture instead of @pytest.mark.parametrize(indices, [string], indirect=True)"

This reverts commit 2a3e611.

Author: SaturnFromTitan