UI: Set default recording format to Fragmented MOV on macOS

[gxalpha]

Description

Changes the default recording container to Fragmented MOV on macOS for release builds.

See also #10331 and #10482 for additional context.

Motivation and Context

In 22205d5 (#10482), the change to default to Fragmented MP4/MOV on all platforms was reverted due to compatibility issues with the default video player on Windows.
On macOS however, the default player (QuickTime Player) works fine with fragmented formats, and instead is unable to play MKV files (which have always been the default format for OBS). This change makes videos with the default settings playable on macOS with the default player.

How Has This Been Tested?

macOS 14.4.1
Created a new profile without this change, witnessed the default container to be MKV.
Created a new profile with this change and saw that the default was Fragmented MOV.

Types of changes

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

Checklist:

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

[jcm93]

Just wanted to note that fmp4 and fmov are not completely free of issues in QuickTime. The formats do play back and seek, but QuickTime features available with ordinary .mov / .mp4 files such as trim, rotate/flip transforms, and actions like remove audio / video are unavailable.

Ultimately I still think fmp4 is a better default than mkv, but wanted to note those caveats. The QuickTime editing deficiencies with fmp4/fmov are filed with Apple as FB13710163.