Support menu item visible length in autocomplete combobox

[interactivellama]

Currently in Combobox we have

	/**
	 * Determines the height of the menu based on SLDS CSS classes. This only applies to the readonly variant. This is a `number`.
	 */
	readOnlyMenuItemVisibleLength: PropTypes.oneOf([5, 7, 10]),

We should deprecated this property and make it menuItemVisibleLength and allow it to apply to autocomplete Comboboxes also.

Here is an example prop deprecation in App Launcher. https://github.com/salesforce/design-system-react/blob/master/components/app-launcher/index.jsx#L136

[interactivellama]

@PaulaIoana This is probably the better path forward than the solution I mentioned in the meeting.