Links in pinned messages aren't clickable or discoverable.

### Steps to reproduce

1. Write an important message with a bunch of markdown links in it
2. Pin it
3. Discover that the links aren't shown in the pinned message, making the message incoherent - you don't even know some of the text has links on it, so you don't seek ways of clicking them.
4. Click on the message in frustration
5. Get taken to the actual message in the timeline
6. Discover that it was full of links after all

### Outcome

#### What did you expect?

Show the links in the pinned message, and let the user click on them.

#### What happened instead?

Frustration.

### Operating system

_No response_

### Application version

_No response_

### How did you install the app?

develop

### Homeserver

_No response_

### Will you send logs?

Yes