Move custom FPS property next to its FPS

[norihiro]

Description

This PR moves the order of the properties on the browser source.

Current properties	Revised properties

Motivation and Context

The two properties "Use custom frame rate" and "FPS" control the FPS so that these properties should be located next to each.

The commit e65bc98 moved the other property "Control audio via OBS" in between the FPS properties. Assuming the commit e65bc98 wanted to make "Control audio via OBS" more visible, I moved "Use custom frame rate" down, instead of moving "FPS" up.

How Has This Been Tested?

Built and ran on Fedora 35, and took the screenshots above.

Types of changes

• Tweak (non-breaking change to improve existing functionality)

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.