obtain CE from mongoose instance, not global driver config

Author: baileympearson

lib/model.js

@@ -69,7 +69,6 @@ const minimize = require('./helpers/minimize');
 const MongooseBulkSaveIncompleteError = require('./error/bulkSaveIncompleteError');
 const ObjectExpectedError = require('./error/objectExpected');
 const decorateBulkWriteResult = require('./helpers/model/decorateBulkWriteResult');
-const driver = require('./driver');
 const modelCollectionSymbol = Symbol('mongoose#Model#collection');
 const modelDbSymbol = Symbol('mongoose#Model#db');
 const modelSymbol = require('./helpers/symbols').modelSymbol;
@@ -4881,7 +4880,7 @@ Model.compile = function compile(name, schema, collectionName, connection, base)
 };
 
 Model.clientEncryption = function clientEncryption() {
-  const ClientEncryption = driver.get().ClientEncryption;
+  const ClientEncryption = this.base.driver.get().ClientEncryption;
   if (!ClientEncryption) {
     throw new Error('The mongodb driver must be used to obtain a ClientEncryption object.');
   }