Prioritize "low priority" over "direct chat" in roomList categories

There's no exact right or wrong here, but if a room was explicitly
marked as "low priority", we should honor this tag.

Fixes a slight inconsistency with the implementation in Element

Fixes #357


(cherry picked from commit 3ea783b370)

src/roomlistmodel.cpp

@@ -346,12 +346,12 @@ QVariant RoomListModel::data(const QModelIndex &index, int role) const
         if (room->isFavourite()) {
             return RoomType::Favorite;
         }
-        if (room->isDirectChat()) {
-            return RoomType::Direct;
-        }
         if (room->isLowPriority()) {
             return RoomType::Deprioritized;
         }
+        if (room->isDirectChat()) {
+            return RoomType::Direct;
+        }
         return RoomType::Normal;
     }
     if (role == UnreadCountRole) {