Ensure we get a valid taxonomy model, or null otherwise (#243)

Author: ryanmitchell

src/Taxonomies/TaxonomyRepository.php

@@ -2,6 +2,7 @@
 
 namespace Statamic\Eloquent\Taxonomies;
 
+use Illuminate\Database\Eloquent\Model;
 use Illuminate\Support\Collection;
 use Statamic\Contracts\Taxonomies\Taxonomy as TaxonomyContract;
 use Statamic\Facades;
@@ -43,7 +44,7 @@ public function findByHandle($handle): ?TaxonomyContract
             return app('statamic.eloquent.taxonomies.model')::whereHandle($handle)->first();
         });
 
-        return $taxonomyModel ? app(TaxonomyContract::class)->fromModel($taxonomyModel) : null;
+        return $taxonomyModel instanceof Model ? app(TaxonomyContract::class)->fromModel($taxonomyModel) : null;
     }
 
     public function findByUri(string $uri, ?string $site = null): ?Taxonomy