When disabling the first item of the second level, the rest of the items appear as a first level items

Problem/Motivation

The second level items appear as first-level items on the mega menu, this issue appears when trying to disable the first child for the first level items if we disable it, the rest of the 2nd level items will appear as first-level items

Steps to reproduce

- item 1
-- item 1a (disabled)
--- item 1a1
--- item 1a2
-- item 1b
-- item 1c
- item 2 
-- item 2a 
- item 3

(the disabled item should have enabled children to produce the issue)

Results in:

- item 1
- item 1b (this is assigned to the wrong parent!) added as 1st level
- item 1c (this is assigned to the wrong parent!) added as 1st level
- item 2 
-- item 2a 
- item 3

Proposed resolution

This needs to load all menu tree without adding onlyEnabledLinks() parameter, then check it the menu link enabled ot not.