applets/kicker: make dashboard highlight span delegate
The highlight for the dashboard sidebar list items is restricted to the label width. This is misleading, as the non-highlighted area will still activate on hover and allow right-clicking (for the few entries that have a context menu). It's also not how our list views usually behave, where the highlight spans the whole delegate.
Instead, remove all the complicated positioning and sizing, and just use the highlight stock - it does the right thing on its own.
| before (pointer area not included in highlight) | after (pointer area included in highlight) |
|---|---|
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