Use "canvas" html id for non-modgui builds

Signed-off-by: falkTX <falktx@falktx.com>

dgl/src/ApplicationPrivateData.cpp

@@ -67,7 +67,11 @@ Application::PrivateData::PrivateData(const bool standalone)
     DISTRHO_SAFE_ASSERT_RETURN(world != nullptr,);
 
     puglSetWorldHandle(world, this);
+   #ifdef __EMSCRIPTEN__
+    puglSetClassName(world, "canvas");
+   #else
     puglSetClassName(world, DISTRHO_MACRO_AS_STRING(DGL_NAMESPACE));
+   #endif
 }
 
 Application::PrivateData::~PrivateData()

distrho/src/DistrhoUIPrivateData.hpp

@@ -108,6 +108,7 @@ public:
     explicit PluginApplication(const char* className)
         : DGL_NAMESPACE::Application(DISTRHO_UI_IS_STANDALONE)
     {
+       #if defined(__MOD_DEVICES__) || !defined(__EMSCRIPTEN__)
         if (className == nullptr)
         {
             className = (
@@ -120,6 +121,10 @@ public:
             );
         }
         setClassName(className);
+       #else
+        // unused
+        (void)className;
+       #endif
     }
 
     void triggerIdleCallbacks()