(bug) change size partitioning (L|R) bug

[NamelessGO]

Describe the bug
The add-on fuction, change size partitioning (L|R), is making the add-on use less space when reopening the "add" - tab used to create flashcards

To Reproduce
Steps to reproduce the behavior:

1. Open a PDF
2. Choose any "change size partitioning" (L|R)
3. Close "add",
4. Open "add", there you will see that the add-on/PDF will use less space of the bottom

Expected behavior
The add-on, after closing the window on 90|10 or any other R|L format should return to using the bottom part, adjacent to tags

Screenshots

Normal behavior L|R set to 50|50, ignore the bonus issue in the right, its present only in the Windows machine (had problems with Qt before, could be why it is appearing)

Normal behaviour, L|R set to 10|90

Problem happens when you reopen the "add"

Bug don't get fixed right away by changing to 50|50

Solution

1. if you have the same problem, first, change the L|R to 50|50 (you need to have a pdf on display for the L|R to appear)
2. close "add"
3. reopen, it should display as normal again

Environment (please complete the following information):

• OS: MacOS 2.1.55 (Beta4) (will add the version at afternoon, or tmw)
  OS: Windows 10, outdated, Public-University PC (Version ⁨2.1.54 (b6a7760c)⁩ Qt5)

[NamelessGO]

Related to #349