fix(gui): explicitly set GLSL profile in shaders

[Exotic0015]

For some reason, current Nvidia drivers on Linux don't set a default OpenGL profile:

OpenGL version string: 4.6.0 NVIDIA 570.124.04
OpenGL shading language version string: 4.60 NVIDIA
OpenGL context flags: (none)
OpenGL profile mask: (none)

While other vendors do, an example from an AMD gpu:

OpenGL version string: 4.6 (Compatibility Profile) Mesa 25.0.1
OpenGL shading language version string: 4.60
OpenGL context flags: (none)
OpenGL profile mask: compatibility profile

This causes shaders used in model previews to fail compilation, making them not render with the logs containing the following lines, among others:

QOpenGLShader::compile(Vertex): 0(2) : error C0201: unsupported version 150
QOpenGLShader::compile(Fragment): 0(2) : error C0201: unsupported version 150

This PR works around this issue specifying the used GLSL profile in the shader sources. This is fully spec compliant, as can be seen here.

[craftablescience]

awesome, thanks! I don't have an nvidia gpu on any of my machines, so didn't even know this was a bug