Fix PDF cert gereration/regeneration and URLs.

Since cert_html_view_enabled is deprecated and set default true,
PDF certificates are not appearing for learners and staff also
unable to regenerate them.

LEARNER-4520

openedx/core/djangoapps/programs/tests/test_utils.py

@@ -1002,6 +1002,20 @@ class TestProgramDataExtender(ModuleStoreTestCase):
         Verify that the student's run mode certificate is included,
         when available.
         """
+        certificates = [
+            {
+                'id': 1,
+                'name': 'Test Certificate Name',
+                'description': 'Test Certificate Description',
+                'course_title': 'tes_course_title',
+                'signatories': [],
+                'version': 1,
+                'is_active': True
+            }
+        ]
+        self.course.certificates = {'certificates': certificates}
+        self.course = self.update_course(self.course, self.user.id)
+
         test_uuid = uuid.uuid4().hex
         mock_get_cert_data.return_value = {'uuid': test_uuid} if is_uuid_available else {}
         mock_html_certs_enabled.return_value = True