manager,context: remove launchcount adjustment

while theoretically a good idea on paper, this makes for super awkward to debug behavior between applications and users/systems. when searching for dolphin 'do' in kickoff it could rank ksudoku first but when doing the same in krunner it could rank dolphin first, entirely dependent on a magic number that nobody knows about. this gets even more fun when you have different users compare results, such as in a bug report.

there are certainly ways to implement this feature in a smarter fashion (global, contextually bound to a query, etc), but ultimately the problem of reproducibility remains

let's remove this instead. it was a very niche feature that I am sure had its fans, but on the balance, muscle memory probably achieves the same end result