Fix wrong setting hiding the sources tab on content provider page.
Motivation and context
Search tabs were not making use of tab history.
Sources tab should be visible to admins even if users can't create them.
Checklist
[x] I have read and followed the CONTRIBUTING guide.
[x] I confirm that I have the authority necessary to make this contribution on behalf of its copyright owner and agree
to license it to the TeSS codebase under the
BSD license.
Summary of changes
Motivation and context
Checklist