Publicize (Auto Share) Adding Image Caption in Description When Sharing on Facebook

### Impacted plugin

Jetpack, Social

### What

Publicize (Auto Share) is adding Image Caption Texts on shared Facebook Post.

### How

**How to Reproduce?**

1. Go to the **Posts** section in WP Admin to create a new post.
2. In the post, add the post title, then add an image with a Caption and some texts below the image » [Example Screenshot](https://user-images.githubusercontent.com/52444539/192987887-c148bbc5-1a44-4288-b4a7-095ff5f16c5e.jpg).
3. Publish the post and share it on Facebook via the Jetpack Auto Share feature.
4. Go to the Facebook Page, and you will see the description of the post on Facebook starting with Image Caption » [Example Screenshot](https://user-images.githubusercontent.com/52444539/192990109-88665a43-3f66-47b9-a45f-7a00688297b3.jpg).

**Temporary Workaround:**

If we add an excerpt to the post or custom message [below the Auto Share option](https://user-images.githubusercontent.com/52444539/192990927-f6f9a86b-034f-4e4d-9127-9426212c8ffc.jpg) By Jetpack, then the post will not be shared with the Image Caption.

Reproduce the issue using the listed WordPress Posts and Jetpack Auto Share steps, then trace the Publicize sharing path for Facebook posts. Compare behavior with and without an excerpt or custom message; done means the image caption no longer starts the Facebook description when neither is provided.

Written by the indexing model from the issue text.