There is currently no customisation via the console for this (as far as I know), but as a work around for the table view you could edit the /opt/zammad/app/assets/javascripts/app/controllers/search.coffee file and edit the available columns here:
At least that way should™ be update-proof. It only visually hides the tab though. @Stubenhocker’s approach is a lot cleaner since only the relevant data is being pulled.
As always:
I’m not a web dev or anything at all and i didn’t try that first. This should hide ALL elements that are classified as tabandjs-tabChatSession which are also a descendant of a detail-search-header object. So if anything else uses this combination, that’s probably gone too.
There’s most likely a better way to achieve this but i don’t know it :>.