Work graph types are incorrectly marked complete

[llvm-beanz]

Description
Several of the Work Graph types are created as complete types but they're not actually complete. This causes problems emitting diagnostics:

https://github.com/microsoft/DirectXShaderCompiler/blob/staging-sm-6.8/tools/clang/lib/Sema/SemaHLSL.cpp#L3890

Actual Behavior
We should not mark types as complete until they are actually complete.

Environment

• DXC version: SM 6.8 Staging branch
• Host Operating System: Any

[llvm-beanz]

This was fixed in #5793.