Fix YouTube not downloading

[antonpup]

Fixes #2555

Title

Fixes certain YouTube videos not downloading

Description

Adds "/best" by default. Courtesy of [gamer191](#2547 (comment))

Related Issue

Fixes #2555

Motivation and Context

Some YouTube videos do not download and error out.

How Has This Been Tested?

I was able to download videos I couldn't before.

Screenshots (if appropriate)

N/A

Types of Changes

• Bug fix (non-breaking change which fixes an issue)
• [] New feature (non-breaking change which adds functionality)
• [] Breaking change (fix or feature that would cause existing functionality to change)

Checklist

• My code follows the code style of this project
• [] My change requires a change to the documentation
• [] I have updated the documentation accordingly
• I have read the CONTRIBUTING document
• [] I have added tests to cover my changes
• [] All new and existing tests passed