[5.0] Better check for empty options for legacy XTD Buttons

[Fedik]

Pull Request for Issue # .

Summary of Changes

A Better check for empty options for legacy XTD Buttons.
A legacy butons may have an empty options as:

$button = new CMSObject();
$button->options  = '';

Then ?? will not work.

Testing Instructions

Code review

Link to documentations

Please select:

• Documentation link for docs.joomla.org:
• No documentation changes for docs.joomla.org needed
• Pull Request link for manual.joomla.org:
• No documentation changes for manual.joomla.org needed

[HLeithner]

@joeforjoomla if this works for you @Fedik (or any other maintainer) can merge this

[joeforjoomla]

@HLeithner Yes this works for me

[HLeithner]

thanks