Fix various bugs introduced with heading
Summary:
This fixes:
- Indented notifications line (it's back)
- Heading being non-clickable
- Buttons not being right-aligned in history
- Keyboard navigation
- Long app names
Reviewers: Plasma, broulik
Reviewed By: Plasma, broulik
Subscribers: ngraham, plasma-devel
Tags: Plasma
Differential Revision: https://phabricator.kde.org/D29234