formatted_body shown in notifications

#### Describe the bug
The formatted_body contents are shown verbatim in notifications, especially pills which are `@mxid` are shown verbatim instead of the useful parts.

#### To Reproduce
get pinged

#### Expected behavior
either show proper markup in notifications if supported, or don't at all

#### Screenshots
/

#### Smartphone (please complete the following information):
- Device: [e.g. Samsung S6]
- OS: Android 10

#### Additional context
- App version and store 1.1.12
- Homeserver: [e.g. matrix.org]

Add any other context about the problem here.