WB-291: Update MachineCast set method to handle uninitialized machines

Changed the set method in MachineCast to return null when the machine should not be initialized. This prevents errors when attempting to set values on uninitialized machines and ensures that only properly initialized machines are processed.

src/Casts/MachineCast.php

@@ -54,8 +54,12 @@ public function get(
      * @param  TSet|null  $value
      * @param  array<mixed>  $attributes
      */
-    public function set(Model $model, string $key, mixed $value, array $attributes): string
+    public function set(Model $model, string $key, mixed $value, array $attributes): ?string
     {
+        if ($model->shouldInitializeMachine() === false) {
+            return null;
+        }
+
         if (is_string($value)) {
             return $value;
         }