Parametrize `VoldAidlTest` on declared instances

Make `VoldAidlTest` pass on devices that don't have the
`android.system.vold.IVold` service declared.

Test: atest VtsHalVendorVoldTest
Bug: 386461529
Change-Id: I498b00948a15a4ddbf7100b10c870ec4b2efa50a