Notice: Trying to access array offset on value of type null in panels_renderer_editor->get_style()

I'm getting a notice on editing a Panel variant content.

Notice: Trying to access array offset on value of type null in panels_renderer_editor->get_style() (line 1152 of panels/plugins/display_renderers/panels_renderer_editor.class.php).

The problem seems to be on the display_renderer plugin, on the get_style function when there in certain cases there is not a valid $type value and makes the switch statement not evaluate, and thus the $style variable being undefined (null).

I've added a little extra clause at the beginning of the if statement to check if the key we are trying to access is actually set. That seems to fix the notice.