Possible memory leak when starting session with lazy @Reference entity

Duplicate of #3513 for milestone 3.0.0

Describe the bug
Metaspace keep increasing without dropping down after repeated query with a new session.
I am not sure if this helps, but I found many $$ReferenceProxy in the heap.

To Reproduce
Steps to reproduce the behavior:

1. Create an entity with @Reference like: @Reference(lazy = true, idOnly = true, ignoreMissing = true)

2. Query the entity repeatedly like:

   FindOptions options = new FindOptions();
   options.sort(Sort.descending("_id"));
   options.limit(1);
   for (int i = 0; i < loop; i++) {
   options.skip(i);
   Datastore ds = getMorphiaDatastore();
   List tmp = new ArrayList<>();
   try(MorphiaSession s = ds.startSession()){
   Query q = s.find(ClazzWithRef, options).filter();
   MorphiaCursor cursor = q.iterator();
   //tmp = cursor.toList();
   cursor.close();
   }
   }

Expected behavior
Metaspace should drop after GC

** Please complete the following information: **

• Server Version: 8.0.4
• Driver Version: 5.3.1
• Morphia Version: 2.5.0

Additional context
Tested with entity with no @Reference is fine.
Tested without starting a new session is also fine.

Read the linked duplicate issue #3513 first, then run the provided Java reproduction with lazy @Reference and repeated new MorphiaSession instances. Compare memory behavior with and without @Reference and with sessions disabled; done means identifying and preventing the retained $$ReferenceProxy/metaspace growth while preserving the reported query behavior.