GHSA-88pr-878c-24wf: Flowise: Authenticated arbitrary file write in the `S3 Directory` document loader via unsanitized S3 object keys

Flowise has a security flaw where authenticated users can write files anywhere on the server's filesystem through the S3 Directory document loader. The vulnerability occurs because the code doesn't check for path traversal sequences (like `../` which moves up directories) when processing S3 object keys, allowing an attacker to write files outside the intended temporary directory.