fix: 잘못된 메소드 호출 수정

Author: MU-Software

app/participant_portal_api/serializers/file.py

@@ -18,7 +18,7 @@ def create(self, validated_data: dict) -> PublicFile:
         new_file = PublicFile(file=validated_data["file"])
         new_file.clean()
 
-        if new_file.hash and (pf := PublicFile.objects.filter(hash=new_file.hash).exists()):
+        if new_file.hash and (pf := PublicFile.objects.filter(hash=new_file.hash).first()):
             return pf
 
         new_file.save()