Child window popout support that supports zooming

[david-trumid]

Recently we ran into an issue where the popout windows were not opening in the correct position or the correct size, we narrowed it down to the _getScreenRect in Layout. We patched it with something like the following

  /** @internal */
    _getScreenRect(node: TabNode) {
        const zoomRatio = this.currentWindow?.devicePixelRatio || 1;
        const rect = node!.getRect()!.clone();
        const bodyRect: DOMRect = this.selfRef.current!.getBoundingClientRect();
        const navHeight = Math.min(80, this.currentWindow!.outerHeight - (this.currentWindow!.innerHeight * zoomRatio));
        const navWidth = Math.min(80, this.currentWindow!.outerWidth - (this.currentWindow!.innerWidth * zoomRatio));
        rect.x = Math.round(((rect.x + bodyRect.x) * zoomRatio) + this.currentWindow!.screenX + navWidth);
        rect.y = Math.round(((rect.y + bodyRect.y) * zoomRatio) + this.currentWindow!.screenY + navHeight);
        rect.height = Math.round(rect.height * zoomRatio);
        rect.width = Math.round(rect.width * zoomRatio);

        return rect;
    }