fix: improve null safety in ReadySystem, MatchManager, and MatchUtility (#135)

Co-authored-by: Flegma <Flegma@users.noreply.github.com>

Author: Flegma

src/FiveStack.Services/MatchManager.cs

@@ -83,14 +83,15 @@ public void Init(MatchData match)
 
     public MatchMap? GetCurrentMap()
     {
-        if (_matchData == null || _matchData.current_match_map_id == null)
+        var matchData = _matchData;
+        if (matchData == null || matchData.current_match_map_id == null)
         {
             return null;
         }
 
-        return _matchData?.match_maps.FirstOrDefault(match_map =>
+        return matchData.match_maps.FirstOrDefault(match_map =>
         {
-            return match_map.id == _matchData.current_match_map_id;
+            return match_map.id == matchData.current_match_map_id;
         });
     }
 

src/FiveStack.Services/ReadySystem.cs

@@ -233,7 +233,7 @@ public void SendReadyMessage(CCSPlayerController player)
             return;
         }
 
-        bool isReady = _readyPlayers[player.UserId.Value];
+        _readyPlayers.TryGetValue(player.UserId.Value, out bool isReady);
 
         string readyWord = isReady ? _localizer["ready.ready"] : _localizer["ready.not_ready"];
         string colored = isReady

src/FiveStack.Utilities/MatchUtility.cs

@@ -57,7 +57,7 @@ string playerName
                     ? matchData.lineup_1.tag
                     : matchData.lineup_2.tag;
 
-            if (tag == null || tag == "")
+            if (string.IsNullOrEmpty(tag))
             {
                 return null;
             }