[Kicker/Kickoff] Re-word "Manage <app>..." menu item for greater clarity
Summary:
Even with the Discover icon added in D23623, the text is still fairly unclear,
especially for the common case of wanting to uninstall the app.
This patch re-words the menu item to add that all-important word "Uninstall", while not
losing any of the current meaning.
Test Plan:
Reviewers: VDG, Plasma, hein, nicolasfella
Reviewed By: nicolasfella
Subscribers: plasma-devel
Tags: Plasma
Differential Revision: https://phabricator.kde.org/D23652