App polish part 2 (#1118)

- Fix sheet backgrounds in dark mode.
- Fix background colours for reaction buttons.
- Reply view layout.
- Update separator colours.
- Don't show sender name/avatar in DMs.
- Fix inconsistent line heights with formatted body text.
- Use plain text for reply
- Increase tappable size of collapsed state changes button.
- Blockquote layout and text colour.
- Tap to expand the topic in room details.
- Change the topic and security font size in room details.
- Add cancel button when inviting someone to an existing room.
- Reword Add Friends to Add People in start chat screen.
- Update compound.

ElementX/Sources/Screens/HomeScreen/View/HomeScreenRoomCell.swift

@@ -41,7 +41,7 @@ struct HomeScreenRoomCell: View {
                     .padding(.vertical, verticalInsets)
                     .overlay(alignment: .bottom) {
                         Rectangle()
-                            .fill(Color.compound._borderRowSeparator)
+                            .fill(Color.compound.borderDisabled)
                             .frame(height: 1 / UIScreen.main.scale)
                             .padding(.trailing, -horizontalInsets)
                     }