deps.windows: Add VPL debug library

[RytoEX]

Description

deps.windows: Install VPL Debug library if present

Also clean up some stray whitespace.

CI: Add VPL Debug build

Similar to AJA's NTV2 library, it seems that VPL requires a separate Debug library to be able to build OBS Studio in Debug with VPL. Use the same technique that we used for NTV2 for VPL.

Motivation and Context

Want to be able to build OBS Studio in Debug with QSV+VPL enabled.

How Has This Been Tested?

Tested locally on Windows 11 by building the VPL dependency in Debug and then building OBS Studio in Debug with a VPL enabled branch.

Types of changes

• Bug fix (non-breaking change which fixes an issue)

• 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.