Default to unknown certificate type translation string.

src/components/ProfilePage/Certificates.jsx

@@ -78,7 +78,7 @@ class Certificates extends React.Component {
                 {intl.formatMessage(get(
                   messages,
                   `profile.certificates.types.${certificateType}`,
-                  messages['profile.certificates.types.verified'],
+                  messages['profile.certificates.types.unknown'],
                 ))}
               </p>
               <h4 className="certificate-title">{courseDisplayName}</h4>

src/components/ProfilePage/Certificates.messages.jsx

@@ -21,6 +21,11 @@ const messages = defineMessages({
     defaultMessage: 'Professional Certificate',
     description: 'A type of certificate a user may have earned',
   },
+  'profile.certificates.types.unknown': {
+    id: 'profile.certificates.types.unknown',
+    defaultMessage: 'Certificate',
+    description: 'The string to display when a certificate is of an unknown type',
+  },
 });
 
 export default messages;