ScriptUI: optional `bounds` prop for "tab" control

[fartinmartin]

I believe the bounds prop should be optional when creating a "tab" control. This removes this error I was receiving:

No overload matches this call.
  The last overload gave the following error.
    Argument of type '"tab"' is not assignable to parameter of type '"treeview"'.

when attempting:

var tabbedPanel = Window.add("tabbedpanel", undefined, undefined, { name: "tabbedPanel" });
var tab1 = tabbedPanel.add("tab", undefined, undefined, { name: "tab1" });