Update glslang submodule

[oltolm]

This is also necessary to fix the GCC build.

[hrydgard]

Can you explain why we need to add two submodules? Also, this didn't quite build.

[oltolm]

I think they are needed by glslang now, I am not sure, I'll double check. It does not build for different reasons. On Windows I didn't add the new submodules to MSVC solution because I don't use it. On other systems that use CMake the problems are different.

[hrydgard]

Well, I don't want to add code that we're not using. I'm doubtful this is needed since it's not needed on the other platforms. We carry all the headers and stuff we need in the current dependencies.

[oltolm]

This is from glslang\CHANGES.md

## 14.1.0 2024-03-08
* Add SPIRV-Tools-opt dependency if ENABLE_OPT

If I disable ENABLE_OPT then CMake prints the warning

spirv-tools not linked - illegal SPIRV may be generated for HLSL

To disable this warning ENABLE_HLSL needs to be disabled.

option(ENABLE_HLSL "Enables HLSL input support" ON)

What should I do? Should I disable ENABLE_OPT and ENABLE_HLSL?

[hrydgard]

ENABLE_HLSL should be disabled. We do not use HLSL as input to glslang currently.

In addition, ENABLE_OPT should also be fine to disable. Though it may be interesting to experiment with using it at some point.

[hrydgard]

This PR still adds the submodules, please remove them.

[oltolm]

I have removed them.