Respect new Laravel accessors's approach

Fix getting a value from a one-word `\Illuminate\Database\Eloquent\Casts\Attribute`-returning accessors

src/Eloquent/Model.php

@@ -155,8 +155,12 @@ public function getAttribute($key)
  }
 
  // This checks for embedded relation support.
- if (method_exists($this, $key) && ! method_exists(self::class, $key)) {
- return $this->getRelationValue($key);
+ if (
+ method_exists($this, $key)
+ && ! method_exists(self::class, $key)
+ && ! $this->hasAttributeGetMutator($key)
+ ) {
+ return $this->getRelationValue($key);
  }
 
  return parent::getAttribute($key);