Update migration

Author: daveearley

backend/database/migrations/2024_12_09_234323_add_notes_to_attendees_table.php

@@ -8,13 +8,19 @@
     public function up(): void
     {
         Schema::table('attendees', static function (Blueprint $table) {
+            if (Schema::hasColumn('attendees', 'notes')) {
+                return;
+            }
             $table->text('notes')->nullable();
         });
     }
 
     public function down(): void
     {
         Schema::table('attendees', static function (Blueprint $table) {
+            if (!Schema::hasColumn('attendees', 'notes')) {
+                return;
+            }
             $table->dropColumn('notes');
         });
     }