[SPIR-V] Remove bug report request when inline SPIR-V is used

[sudonatalie]

By design, it's possible to generate arbitrary and therefore invalid SPIR-V with inline SPIR-V. In this case, validation errors are much less likely to be the result of compiler bugs, so we should remove the following note from our output when inline SPIR-V features are used:

note: please file a bug report on https://github.com/Microsoft/DirectXShaderCompiler/issues with source code if possible

[sudonatalie]

@cassiebeckley Can you look into this change?