matdbg: indicate shader model (#8504)

Shader model (desktop or mobile) wasn't really accounted for
in the UI. This means that we will get shaders that look like
duplicates (same variant). In this work, we pass the current
shader model from engine into the frontend and filter out
variants of a different shader model.

Moreover, for matinfo, we use a specific dbg shader model (matinfo)
to indicate it is in that mode. We add UI in matinfo to show the
shadermodel.

So UI updates as well.

libs/matdbg/src/DebugServer.cpp

@@ -122,8 +122,11 @@ private:
     DebugServer* mServer;
 };
 
-DebugServer::DebugServer(Backend backend, ShaderLanguage shaderLanguage, int port)
-        : mBackend(backend), mShaderLanguage(shaderLanguage) {
+DebugServer::DebugServer(Backend backend, ShaderLanguage shaderLanguage,
+        DbgShaderModel perferredShaderModel, int port)
+    : mBackend(backend),
+      mShaderLanguage(shaderLanguage),
+      mPreferredShaderModel(perferredShaderModel) {
 
     #if !SERVE_FROM_SOURCE_TREE
     ASSET_MAP["/index.html"] = {