Widget Visibility: doesn't work with third party blocks

### Impacted plugin

Jetpack

### Steps to Reproduce

1. Got to Widgets
2. Add a custom block or thirs party block
2. Set the vibility settings
3. Save

### A clear and concise description of what you expected to happen.

The block should show on specified pages

### What actually happened

The visibility setting has no effect. When coming back to the widget settings page, the visibility settings got reset, it seems like it is not saving in the block's attributes.

### Other information

I tested my custom blocks and those plugins :
- [Nova Blocks](https://fr.wordpress.org/plugins/nova-blocks/)
- [GenerateBlocks](https://fr.wordpress.org/plugins/generateblocks/)
- [Contact form 7](https://fr.wordpress.org/plugins/contact-form-7/)
- [Rank Maths SEO](https://fr.wordpress.org/plugins/seo-by-rank-math/)
- [Breadcrumb Navxt](https://fr.wordpress.org/plugins/breadcrumb-navxt/)
- etc.

### Operating System

Windows, Linux

### OS Version

Win 10, Ubuntu 21.04

### Browser

Chrome/Chromium, Firefox

### Browser Version(s)

Latest

Start in Widgets and reproduce the visibility reset with Nova Blocks, GenerateBlocks, Contact Form 7, or Rank Math SEO. Check whether the visibility settings persist in the third-party block's attributes and affect the specified pages; done means they save, remain after returning to the widget settings, and control display.

Written by the indexing model from the issue text.