suppress tab-bar for child-frame of lsp-ui-doc (#704)

`tab-bar-lines-keep-state` is not documented, but it is required to against `tab-bar--update-tab-bar-lines`

Author: buzztaiki

lsp-ui-doc.el

@@ -192,6 +192,8 @@ Only the `background' is used in this face."
     (right-fringe . 0)
     (menu-bar-lines . 0)
     (tool-bar-lines . 0)
+    (tab-bar-lines . 0)
+    (tab-bar-lines-keep-state . 0)
     (line-spacing . 0)
     (unsplittable . t)
     (undecorated . t)