actually change bg color in renderer

dependencies/subprojects/animationwindow/src/AnimationWindow.cpp

@@ -412,4 +412,6 @@ void TDT4102::AnimationWindow::endNuklearDraw() {
 
 void TDT4102::AnimationWindow::setBackgroundColor(TDT4102::Color newBackgroundColor) {
     backgroundColor = newBackgroundColor;
+    SDL_SetRenderDrawColor(rendererHandle, backgroundColor.redChannel, backgroundColor.greenChannel, backgroundColor.blueChannel, backgroundColor.alphaChannel);
+    SDL_RenderClear(rendererHandle);
 }