math/geogebra: Update from 5.0.236.0 to 5.0.260.0

Changelog: https://www.geogebra.org/manual/en/Reference:Changelog_5.0

Also removed shared-mime-info from USES

PR: 210401
Submitted by: Zsolt Udvari <udvzsolt@gmail.com> (maintainer)
Approved by: junovitch (mentor)