UX: Minor cosmetic fixes to the wizard (#11172)

- Does not force users to type a description or a welcome topic
- Adds * marker for required text fields (site title and email)

app/assets/javascripts/wizard/templates/components/wizard-field.hbs

@@ -1,5 +1,11 @@
 <label for={{field.id}}>
-  <span class="label-value">{{field.label}}</span>
+  <span class="label-value">
+    {{field.label}}
+
+    {{#if field.required}}
+      <span class="field-required">*</span>
+    {{/if}}
+  </span>
 
   {{#if field.description}}
     <div class="field-description">{{html-safe field.description}}</div>
@@ -13,3 +19,7 @@
 {{#if field.errorDescription}}
   <div class="field-error-description">{{html-safe field.errorDescription}}</div>
 {{/if}}
+
+{{#if field.extra_description}}
+  <div class="field-extra-description">{{html-safe field.extra_description}}</div>
+{{/if}}