test: fix note e2e test 'fails with non-existing alias'

Because the rejection now happens automatically in the permissions guard it does not get to the controller method and does not report the Content-Type to text/markdown

Signed-off-by: Philip Molares <philip.molares@udo.edu>

test/public-api/notes.e2e-spec.ts

@@ -396,7 +396,6 @@ describe('Notes', () => {
       // check if a missing note correctly returns 404
       await request(testSetup.app.getHttpServer())
         .get('/api/v2/notes/i_dont_exist/content')
-        .expect('Content-Type', /text\/markdown/)
         .expect(404);
     });
   });