[Tests] Skip SNI icon test

The SNI icon test is failing due to seo.com removing their favicon.

A new test to replace it would be needed to check SNI support. Ideally
new tests would not rely on external sites.

deluge/tests/test_tracker_icons.py

@@ -56,6 +56,7 @@ class TestTrackerIcons(BaseTestCase):
         result = await self.icons.fetch('google.com')
         assert result == icon
 
+    @pytest.mark.skip(reason='Site removed favicon, new SNI test will be needed')
     @pytest_twisted.ensureDeferred
     async def test_get_seo_svg_with_sni(self):
         # seo using certificates with SNI support only