🐛 Fixed offer page showing empty name for logged in member

closes https://github.com/TryGhost/Team/issues/1301

- if a logged in member doesn't a name stored, the offer page for them gets bricked  while trying to redeem as the UI doesn't allow submit.
- removes name field for logged-in member if empty

ghost/portal/src/components/pages/OfferPage.js

@@ -245,7 +245,14 @@ export default class OfferPage extends React.Component {
         ];
 
         /** Show Name field if portal option is set*/
-        if (portalName) {
+        let showNameField = !!portalName;
+
+        /** Hide name field for logged in member if empty */
+        if (!!member && !member?.name) {
+            showNameField = false;
+        }
+
+        if (showNameField) {
             fields.unshift({
                 type: 'text',
                 value: member?.name || state.name,