Add missing method definition SetDefaultTimeout()

The header vtkWebGPUConfiguration.h declared this method, but the
definition was missing.

Rendering/WebGPU/vtkWebGPUConfiguration.cxx

@@ -121,6 +121,12 @@ void vtkWebGPUConfiguration::PrintSelf(ostream& os, vtkIndent indent)
   this->Superclass::PrintSelf(os, indent.GetNextIndent());
 }
 
+//------------------------------------------------------------------------------
+void vtkWebGPUConfiguration::SetDefaultTimeout(double t)
+{
+  vtkWebGPUConfigurationInternals::DefaultTimeout = t;
+}
+
 //------------------------------------------------------------------------------
 wgpu::Adapter vtkWebGPUConfiguration::GetAdapter()
 {