[algorithms] If algorithms are only usable, users can still see it through the "diff" panel

Example:

https://www.beat-eu.org/platform/algorithms/diff/anjithgeorge/KBOC_IITKGP_ANJITH_APRIL7_1/10/anjithgeorge/KBOC_IITKGP_ANJITH_APRIL7_1/14/

This option should be removed.

mentioned in merge request !207 (merged)

Status changed to closed by commit 22f8fe94

mentioned in merge request !209 (merged)

mentioned in commit 33d12dd1

mentioned in commit 22f8fe94

mentioned in issue #436 (closed)