Achievements: Save submitted time from API in leaderboards

src/frontend-common/achievements.cpp

@@ -1270,6 +1270,7 @@ void Achievements::GetLbInfoCallback(s32 status_code, std::string content_type,
     LeaderboardEntry lbe;
     lbe.user = entry.username;
     lbe.rank = entry.rank;
+    lbe.submitted = entry.submitted;
     lbe.formatted_score = score;
     lbe.is_self = lbe.user == s_username;
 

src/frontend-common/achievements.h

@@ -51,6 +51,7 @@ struct LeaderboardEntry
 {
   std::string user;
   std::string formatted_score;
+  time_t submitted;
   u32 rank;
   bool is_self;
 };