[FIX]Added a condition allowing to display a tooltip if the description of a preference is not empty

On this task , I was asked to set a condition allowing to display the tooltip if the description of a preference is not empty and if the description of a preference is empty, I just keep the documentation link behind the 'help icon' and remove the tooltip over the 'help icon'.

link of the task :

• https://avan.tech/item70185-Missing-help-text-in-lib-prefs-feature-php#threadId55227
• https://dev.tiki.org/item7430-Missing-help-text-in-lib-prefs-feature-php#threadId9990