Fixed mod_finder JavaScript error

com_finder/autocompleter.js requires Mootools
Improved loading JHtml::_('behavior.framework') of mod_finder
[fix] Accessing undefined elements on Configuration > Text filters
Merge pull request #3073 from jurianeven/master-fix/findermootools

Fixed Finder JavaScript error
Merge pull request #3402 from phproberto/config/undefined

[#33552] [fix] Accessing undefined elements on Configuration > Text filters