fix: Create a better admin UI for PendingNameChange model (#28888)

The current admin UI for the PendingNameChange model has no useful info and is not performant on edit form. This change make the view and edit of the model easier in django admin

Co-authored-by: Simon Chen <schen@edx-c02fw0guml85.lan>

common/djangoapps/student/admin.py

@@ -552,9 +552,20 @@ class UserCelebrationAdmin(admin.ModelAdmin):
     def has_module_permission(self, request):
         return False
 
+
+@admin.register(PendingNameChange)
+class PendingNameChangeAdmin(admin.ModelAdmin):
+    """Admin interface for the Pending Name Change model"""
+    readonly_fields = ('user', )
+    list_display = ('user', 'new_name', 'rationale')
+    search_fields = ('user', 'new_name')
+
+    class Meta:
+        model = PendingNameChange
+
+
 admin.site.register(UserTestGroup)
 admin.site.register(Registration)
-admin.site.register(PendingNameChange)
 admin.site.register(AccountRecoveryConfiguration, ConfigurationModelAdmin)
 admin.site.register(DashboardConfiguration, ConfigurationModelAdmin)
 admin.site.register(RegistrationCookieConfiguration, ConfigurationModelAdmin)