elementary: Check for valid cursor_rect when (un)setting focus
As the cursor_rect for elm_code_widget is not created until the code
widget gets focus, we cannot just assume it is already there when
trying to emit a focus signal. The cursor_rect does not get created
until widget_cursor_update is called.
This fixes an issue where NULL is passed to efl_layout_signal_emit.
To test this, just launch elementary_test and click the Code Editor
test. As soon as you try to click into the Code Editor, this gets
Reviewers: netstar, ajwillia.ms
Reviewed By: netstar
Maniphest Tasks: T7030
Differential Revision: https://phab.enlightenment.org/D6701