[BUG] Utilities are not updated

Description
Subfolders and classes in utils are not updated if multiprocessing is disabled.

Setup

1. Minion configuration: multiprocessing: False
2. Add an example with an OOP style from the documentation to the utilities: https://docs.saltproject.io/en/latest/topics/utils/index.html#utility-modules-code-reuse-in-custom-modules
3. Change the behavior of the class
4. Calling saltutil.sync_all on the master
5. Re-execute the module

Expected behavior
Utilities are being updated.

Versions Report

Additional context
The same situation is with the nested structure in utilities.

Reproduce the issue with multiprocessing disabled, an OOP-style utility example, and saltutil.sync_all, then trace how utility modules and nested subfolders are loaded and refreshed. Done means changed utility classes and nested utilities are updated when the module is re-executed.