obs-outputs: Fix tkhd/mvhd box version with 64-bit timestamps

[derrod]

Description

Fixes an issue where the version of the tkhd and mvhd boxes was not correctly set when using 64-bit durations/timestamps.

Motivation and Context

The larger fields are used when the duration exceeds UINT32_MAX, which in practice would happen around 1193 hours of continuous recording (OBS uses a millisecond timescale for the presentation).

How Has This Been Tested?

Still works normally, overflow condition not specifically tested.

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.