message: fix(SelectedControl): change slider bg token
diff: top: 0;
  left: 0;
  bottom: 0;
  - background-color: var(--vkui--color_background_modal);
  + background-color: var(--vkui--color_segmented_control);
  transition: transform 150ms;
  transform-origin: 0 0;
  border-radius: inherit;
  