TouchInput events are not working for web builds

## Bevy version

0.7

## Operating system & version

Chrome 100 on Android 12

## What you did

Create a sprite following users touch input.

## What you expected to happen

To get `TouchInput` events.

## What actually happened

No `TouchInput` events are being produced.

## Additional information

Mouse position changes only at the start of a touch. I would like touch events rather than mouse position because I want to handle multiple fingers at the same time.