[Registration] Monja Image Validator

### Node Info
* **Repo URL:** https://github.com/andremonjardim/comfyui-image-validator
* **Description:** A professional node to validate if images are multiples of 8, preventing errors in Flux, Upscale and Tiling workflows.
* **Category:** Actions

The issue links the proposed node repository at https://github.com/andremonjardim/comfyui-image-validator; start by reviewing that repository and how ComfyUI-Manager handles node registrations. Confirm whether this node is suitable for the manager's registry and what registration metadata is required. Done means its registration is added in the appropriate format, with the image validator described as checking multiples of 8.

Written by the indexing model from the issue text.