Revert "fix(build): use an older ffmpeg version when packaging (#6070)"

[addaleax]

This reverts commit 4da646a.

Split out from #6122 because the recent 29.x Electron upgrade means we don't need to adopt 31.x right now.

Description

Checklist

• New tests and/or benchmarks are included
• Documentation is changed or added
• I have signed the MongoDB Contributor License Agreement (https://www.mongodb.com/legal/contributor-agreement)

Motivation and Context

• Bugfix
• New feature
• Dependency update
• Misc

Open Questions

Dependents

Types of changes

• Backport Needed
• Patch (non-breaking change which fixes an issue)
• Minor (non-breaking change which adds functionality)
• Major (fix or feature that would cause existing functionality to change)