Sort & Preview Menu

### Your use case

#### What would you like to do?
1. Remove divider line below"sort"
2. Move divider line from below "Appearance" to above it.
3. Use inset divider lines.
4. **Change**:- "Show message previews" to **"Message previews"**
- "Unread first" to **"Unreads first"**
#### Why would you like to do it?
1. Simplifies menu.
2. Improves visual grouping.
3.
- Without the header the labels needed to clearly convey that it is sorting.
- "Preview" implies it's something you are shown, so "Show" can be omitted.
And the checkbox would tell you if it's on/off - Showing/not showing.
#### How would you like to achieve it?
**Before and After**

### Have you considered any alternatives?

_No response_