KateIconBorder: Ensure Dyn Wrap Marker are shown

Test Plan:

• Ensure you have Dynamic Word Wrap *disabled* on KWrite start-up but *Always ON* to show wrap indicators; Config->Appearance->General
• Start KWrite, enter long enough lines
• Hit F10 to enable Dynamic Word Wrap
• Lines should now be wrapped and wrap indicators shown, at least with this patch

Differential Revision: https://phabricator.kde.org/D20431