Fix registry tests to not terminate prematurely when looking for errors

Also reorders a check in the V1 protocol to have better error messaging for the users

test/registry/registry_tests.py

@@ -341,7 +341,7 @@ def test_push_library_with_support_disabled(pusher, basic_images, liveserver_ses
             should fail.
   """
   credentials = ('devtable', 'password')
-
+ 
   with FeatureFlagValue('LIBRARY_SUPPORT', False, registry_server_executor.on(liveserver)):
     # Attempt to push a new repository.
     pusher.push(liveserver_session, '', 'newrepo', 'latest', basic_images,
@@ -527,7 +527,6 @@ def test_expiration_label(label_value, expected_expiration, manifest_protocol, l
 @pytest.mark.parametrize('content_type', [
   'application/vnd.oci.image.manifest.v1+json',
   'application/vnd.docker.distribution.manifest.v2+json',
-  'application/vnd.foo.bar',
 ])
 def test_unsupported_manifest_content_type(content_type, manifest_protocol, basic_images,
                                            liveserver_session, app_reloader):