frontend: Fix rescale dropdown enable desync

[Warchamp7]

Description

Fixes Multitrack Video inadvertently re-enabling the rescale output resolution dropdown.

This is a bandaid solution but settings is a known mess

Motivation and Context

Fixes #11908

How Has This Been Tested?

Toggled Multitrack video on and off. Toggled Use stream encoder for Recording on/off.

Types of changes

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

Checklist:

• I have read the contributing document.
• My code has been run through clang-format.
• My code follows the project's style guidelines
• My code is not on the master branch.
• My code has been tested.
• All commit messages are properly formatted and commits squashed where appropriate.
• I have included updates to all appropriate documentation.