Lists in Markdown don't render/bullets disappear

### Impacted plugin

Jetpack

### Quick summary

When writing a comment, a list made of * or - not only doesn't render properly as a HTML list, but also hides those characters. (At least using default comment form.)

### Steps to reproduce

1. Activate Markdown module on Jetpack, and only it.
2. Browse a blog post with comments open.
3. Type a list using * or -.

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

* Item 1
* Item 2
* Item 3

### What actually happened

Item 1
Item 2
Item 3

### Impact

Most (> 50%)

### Available workarounds?

No but the platform is still usable

### If the above answer is "Yes...", outline the workaround.

_No response_

### Platform (Simple and/or Atomic)

_No response_

### Logs or notes

_No response_

Start by reproducing the issue with Jetpack's Markdown module enabled and the default comment form on a blog post with comments open. Inspect the Markdown handling for comment lists; done means lines beginning with * or - render as an HTML list and the bullet characters are not lost.

Written by the indexing model from the issue text.