wherein not accounting for null values

**Describe the bug**
Using android and trying to use .wherein with a null value just ignores it.
Example:

.whereIn("reservation.cleanBy", listOf(null, firebaseAuth.currentUser!!.uid)
.whereEqualTo("reservation.cleanBy", null) works fine!

**Expected behavior**
The query result should also include the document where the specified value is null

**Smartphone (please complete the following information):**
Emulator API 33

The report names no repository file, test, or entry point. Start by reproducing the Android query with whereIn containing null alongside a non-null user ID, compare it with whereEqualTo(null), and trace the Firebase Emulator Suite query handling. Done means the whereIn result includes documents whose specified value is null.

Written by the indexing model from the issue text.