[BLOCKING] Specific variables in UI do not update on events

Verification builds:
1.6.0 Release_980905

Summary:
When switching between UI Profiles under the settings, variables set within a control do not get read/updated.

The Armour renderer has a pre-set offset difference between "Classic" and "Pocket" ui types which requires a variable to modify the offset; if you wish to maintain it's position. However, the offset is not updated when the screen updates causing the armour to appear in an incorrect position. On reload of the world, the screen is created and the correct offset are used.

Impact:
If a user changes their UI profile the armour receives an offset which breaks the UI. 

Repro Steps:

1. Load MCM-316_UI_Variables.mcpack (Found in #mco_noxcrew slack) in a vanilla world
2. Observe the position of the armour HUD
3. Open the pause menu, then settings, video and change the UI profile to the other option
4. Observe the position of the armour HUD
5. Quit the world
6. Reload the world
7. Observe the position of the armour HUD
8. Open the pause menu, then settings, video and change the UI profile to the original option
9. Observe the position of the armour HUD

Observed Results:
When switching the UI profile the HUD does not maintain it's position. Reloading the world shows it in it's correct position indicating the code is correct however the variable/screen is not updated 

Expected Results:
When switching the UI profile the screen is re-created and thus reads the correct variable, similar to how a binding currently works. 

Screenshots/Videos attached: Yes

https://drive.google.com/open?id=1DakLcC_3XP_7_9bLnZdKvoFIK7ykJKwj 

Note: the video is a demo which features a rectangle to illustrate the movement of the armour. The file found within the mco_noxcrew channel features the whole UI, rather than the stripped back demo version.