applet/digital-clock: back to using sizehelper to calc width
applet/digital-clock: back to using sizehelper to calc width
This partially reverts: !3533 (merged) !3538 (merged)
as I believe the problem they tried to fix was due to wrong timeFormat used in sizehelper, so we should fix that instead of not using sizehelper for width. The later results in the applet constantly changing width with a variable-width font.