The "quick setup" dialog is actually a 'menu', and the "splash screen" block
contains the UI_BLOCK_LOOP flag which causes the buttons' text to align
to the left, however, usually regular buttons have centered text.
As a workaround, add the UI_BLOCK_QUICK_SETUP flag which prevents
the text from being left-aligned.
Differential Revision: https://developer.blender.org/D10486
Reviewed by: Julian Eisel
0c62906a41