Fixes UBSAN warning:

```
/home/milian/projects/kf5/src/extragear/kdevelop/kdevelop/kdevplatform/shell/uicontroller.cpp:232:57: runtime error: member call on address 0x60400043c250 which does not point to an object of type 'UiController'
0x60400043c250: note: object is of type 'Sublime::Controller'
 9c 00 00 25  b8 10 ee ba 89 7f 00 00  20 ec 0f 00 80 60 00 00  80 2a 63 00 60 60 00 00  e8 c0 76 bb
              ^~~~~~~~~~~~~~~~~~~~~~~
              vptr for 'Sublime::Controller'
    #0 0x7f89c8d7c300 in operator() /home/milian/projects/kf5/src/extragear/kdevelop/kdevelop/kdevplatform/shell/uicontroller.cpp:232
```