correct instructions - security incident reporting

These instructions are not always available for a potential security incident; only applies in case of phishing.

https://git.scicore.unibas.ch/scicore/scicore-public-documentation/-/blob/main/scicore-docs/Docs/sciCORE+/securityincidentreport.md?ref_type=heads&plain=1#L19-L23

This will not make it easier for the users to report security incidents. The users who cannot find an "email address" or a "suspicious link" will simply be not motivated to report an incident.

Please remove these lines.