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/Generated/Strings.swift

@@ -68,6 +68,10 @@ public enum L10n {
   public static func actionInviteFriendsToApp(_ p1: Any) -> String {
     return L10n.tr("Localizable", "action_invite_friends_to_app", String(describing: p1))
   }
+  /// Invite people to %1$@
+  public static func actionInvitePeopleToApp(_ p1: Any) -> String {
+    return L10n.tr("Localizable", "action_invite_people_to_app", String(describing: p1))
+  }
   /// Invites
   public static var actionInvitesList: String { return L10n.tr("Localizable", "action_invites_list") }
   /// Learn more