Proposal If a collection configured with encryptedFields is dropped, also drop state collections: enxcol_.<coll>.esc, and enxcol_.<coll>.ecoc

Background & Motivation

Creating a collection for Queryable Encryption (QE) requires drivers also create state collections (full example):

coll = encrypted_client["db"].create_collection("coll", encryptedFields=encrypted_fields)
# Created `coll`, `enxcol_.coll.esc`, and `enxcol_.coll.ecoc`

Dropping a QE collection on an encrypted MongoClient requires drivers drop state collections:

coll.drop()
# Dropped `coll``, `enxcol_.coll.esc`, and `enxcol_.coll.ecoc`

However, if a collection is accidentally dropped with an unencrypted MongoClient, the state collections remain:

unencrypted_client = MongoClient()
unencrypted_client["db"]["coll"].drop() # Only drops `coll`!

This results in orphaned collections.

Create Collection creates all collections describes the reason creating QE collections does not create the state collections on the server:

If create collection in FLE 2 creates 4 collections and 1 secondary index in one create collection invocation this breaks the assumptions of tools like MongoRestore/MongoSync/MongoMirror in that one call to createCollection creates one collection.

However, this rationale may not apply to drop.