Remove degrees and course types from contributor export header about evap

[richardebeling]

@janno42 With the default testdata, both users evap and contributor currently only get an empty excel file when pressing the "Export results" button on the contributor index page (which is the button I think this issue is about, right?). This hindered progress with this issue, as it makes it hard to understand the issue (as there is no data row with these headers).

Do we want to update test data to include some results for the user evap by default?

@Tillbtn @finger813 Executing the following lines in ./manage.py shell_plus already made some data show up for me, maybe that's enough for you for now:

from model_bakery import baker
e = Evaluation.objects.filter(name_de="Softwarearchitektur").first()
u = UserProfile.objects.filter(email="[email protected]").first()
c = baker.make(Contribution, evaluation=e, contributor=u)

It looks like it isn't necessary that there are any actual results for the contributor.

[janno42]

You can login as [email protected] to have useful test data.
@richardebeling Adding some data for contributor is something we can do in addition.