Support to throw exception when read null from Model::createOrFirst.

Author: awesee

src/Model/Builder.php

@@ -575,8 +575,8 @@ public function createOrFirst(array $attributes = [], array $values = [])
     {
         try {
             return $this->create(array_merge($attributes, $values));
-        } catch (UniqueConstraintViolationException $exception) {
-            return $this->where($attributes)->first();
+        } catch (UniqueConstraintViolationException $e) {
+            return $this->where($attributes)->first() ?? throw $e;
         }
     }