[ShaderGraph] Make use of NodeResultType in NodeResult struct instead of just an int to define the result type

[QuackCola]

Summary

The following pr in short replaces all the usage of

public NodeResult( int components, string code, bool constant = false )

with

public NodeResult( NodeResultType resultType, string code, bool constant = false )

while also modifying the NodeResult struct so that it stores the NodeResultType

I also replaced any usage of NodeResultType.Color with NodeResultType.Vector4.

Motivation & Context

Doing it this way makes more sense and will also better support a future change i have cooking up that involves adding
Texture2D and TextureCube NodeResultTypes.

The replacement of NodeResultType.Color with NodeResultType.Vector4 makes sense for me atleast whithin in the context of shhadergraph since it's just another way to represent a float4/vector4.

Nothing really changes for the user except maybe some obsolete warnings on custom c# defined nodes.

Implementation Details

Make some additional tweaks here and there to support the changes and also
obsoleted both

public NodeResult( int components, string code, bool constant = false )

and

NodeResultType.Color

Checklist

• Code follows existing style and conventions
• No unnecessary formatting or unrelated changes
• Public APIs are documented (if applicable)
• Unit tests added where applicable and all passing
• I’m okay with this PR being rejected or requested to change 🙂