applets/kickoff: don't show tooltips with text the user didn't ask for
Kickoff allows you to configure the label style to show the app name, description, both, or both with the description first.
In the first two cases, the user is indicating that they only want one label — just the app name or just the app description.
Right now Kickoff does not honor that, and always shows the second label in a tooltip anyway.
With this commit, Kickoff now only shows the second label in a tooltip if the user wants it. Elided main label text still appears in a tooltip as expected.
BUG: 501380 FIXED-IN: 6.4.0
Test plan: hover over list and grid items with all four display style options. When using the "Name" or "Description" options, you should now only see a tooltip if the visible label is elided, and the tooltip should only show the full non-elided text.