fix: check force script name

[CraigMChen]

According to the following code in repo label-studio

@property
def url(self):
    if settings.FORCE_SCRIPT_NAME and not (settings.HOSTNAME and settings.CLOUD_FILE_STORAGE_ENABLED):
        return settings.FORCE_SCRIPT_NAME + '/' + self.file.url.lstrip('/')
    else:
        return self.file.url

The file path is prefixed with settings.FORCE_SCRIPT_NAME if script name is not null. The SDK should consider this situation when checking whether a file is an uploaded file.