fix: Supress a Settings UI Streching

[suogesi]

change advStreamTrackWidget's vsizetype from Preferred to Fixed which prevent this item stretching in vertical direction

Description

Settings > Output > Output Mode: Advance > Streaming > Streaming Settings > Audio Track
The options would stretch in vertical direction when the window is very height. Now it has a fixed height.

before:

after:

Motivation and Context

Issue: /issues/13286

How Has This Been Tested?

I run it on my Windows 10 laptop and I see it works.

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.