UI: Lock volume meter sliders to LTR to fix RTL slider direction

[WizardCM]

Description

Fixes #5447 where sliders would work in reverse.

Before:

https://user-images.githubusercontent.com/941350/207585709-357d860a-dffc-49a0-85a6-74aee99c0eed.mp4

Motivation and Context

Bugs are bad. Some are relatively easy to fix.

How Has This Been Tested?

On Windows with Qt set to launch in RTL mode.

Types of changes

• Bug fix (non-breaking change which fixes an issue)

Checklist:

• [x] My code has been run through clang-format.
• [x] I have read the contributing document.
• [x] My code is not on the master branch.
• [x] The code has been tested.
• [x] All commit messages are properly formatted and commits squashed where appropriate.
• [x] I have included updates to all appropriate documentation.