message: fix(PanelHeader): bring back vkcom styles
diff: content: "";
  }
  +.PanelHeader--vkcom.PanelHeader--sizeX-regular:not(.ModalPageHeader__in)
  + .PanelHeader__in {
  + border-top-left-radius: 8px;
  + border-top-right-radius: 8px;
  + box-shadow: 0 0 0 var(--thin-border) var(--input_border) inset;
  + border-bottom: none;
  +}
  +
  .PanelHeader--vkcom .PanelHeader__content {
  text-align: center;
  }
  