App Layout - Toolbar shouldn't collapse with an empty list

### Steps to reproduce

1. Make sure the home screen has a height smaller than the viewport height
2. Scroll down

### Outcome

#### What did you expect?

For nothing to move as there's nothing to scroll

#### What happened instead?

The "all chats" header collapses and that feels odd as there's nothing to scroll. I believe we should prevent header collapse behaviour when the list height is smaller than the viewport height

### Your phone model

_No response_

### Operating system version

_No response_

### Application version and app store

_No response_

### Homeserver

_No response_

### Will you send logs?

No

### Are you willing to provide a PR?

No