libobs/graphics: Add support for param assign with type constructor

[exeldro]

Description

Add support for: uniform float4 test = float4(1,0,0,1); next to the existing: uniform float4 test = {1,0,0,1};

Motivation and Context

Support more shader stuff. This helps converting glsl shaders more easily.

How Has This Been Tested?

On windows 11 by having a shader with the new param assignment

Types of changes

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

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.