Add "why do you want to join" field to invite requests (#10524)

* Add "why do you want to join" field to invite requests

Fix #10512

* Remove unused translations

* Fix broken registrations when no invite request text is submitted

app/javascript/styles/mastodon/widgets.scss

@@ -377,6 +377,10 @@
     border: 0;
   }
 
+  strong {
+    font-weight: 700;
+  }
+
   thead th {
     text-align: center;
     text-transform: uppercase;
@@ -414,6 +418,11 @@
     }
   }
 
+  &__comment {
+    width: 50%;
+    vertical-align: initial !important;
+  }
+
   @media screen and (max-width: $no-gap-breakpoint) {
     tbody td.optional {
       display: none;