Hello,
This is the new standard default as decided by the manufacturer, and we don't provide UI options for such specific settings on our end. If this helps, most Yealinks have a dedicated "X" button for ending the call. It takes a little getting used to, but it's quite handy.
But if you really wish to change this behavior you will need to speak with Yealink to give you the correct settings, and use your own custom templates to enforce those settings - not recommended though as you have to maintain your own templates and they might not work in future versions.