js: force clear color in TextureSource if we are not connected, to avoid artifacts

Author: jcelerier

src/plugins/score-plugin-js/JS/Qml/TextureSource.cpp

@@ -165,6 +165,11 @@ void TextureSourceRenderer::render(QRhiCommandBuffer* cb)
       r->render(*cb);
     }
   }
+  else
+  {
+    cb->beginPass(this->renderTarget(), Qt::transparent, {});
+    cb->endPass();
+  }
   update();
 }