Use firstOrNew() on asset save when asset has no model (#457)

* go back to firstOrNew() on assets

* Add test coverage

Author: ryanmitchell

src/Assets/Asset.php

@@ -145,7 +145,7 @@ public static function makeModelFromContract(AssetContract $source, $meta = [])
         }
 
         if (! $model) {
-            $model = app('statamic.eloquent.assets.model')::make([
+            $model = app('statamic.eloquent.assets.model')::firstOrNew([
                 'container' => $source->containerHandle(),
                 'folder' => $source->folder(),
                 'basename' => $source->basename(),

tests/Assets/AssetTest.php

@@ -206,4 +206,24 @@ public function uploads_a_file()
         Event::assertDispatched(AssetUploaded::class, fn ($event) => $event->asset === $asset);
         Event::assertDispatched(AssetCreated::class, fn ($event) => $event->asset === $asset);
     }
+
+    #[Test]
+    public function can_save_an_asset_made_on_the_container()
+    {
+        Event::fake();
+
+        $this->assertCount(6, AssetModel::all());
+
+        $asset = $this->container->makeAsset('a.jpg');
+
+        $this->assertNull($asset->model());
+
+        $asset->save();
+
+        $this->assertNotNull($asset->model());
+
+        Event::assertDispatched(AssetSaved::class, fn ($event) => $event->asset === $asset);
+
+        $this->assertCount(6, AssetModel::all());
+    }
 }