Introduce the LuaCsLogger class and make everything use that instead

Barotrauma/BarotraumaTest/LuaCs/HookPatchTests.cs

@@ -18,10 +18,9 @@ namespace TestProject.LuaCs
             // same methods, otherwise we get script ownership exceptions.
             luaCs = luaCsFixture.LuaCs;
 
-            luaCs.MessageLogger = (prefix, o) =>
+            LuaCsLogger.MessageLogger = (o) =>
             {
-                o ??= "null";
-                output?.WriteLine(prefix + o);
+                output?.WriteLine($"{o}");
             };
 
             UserData.RegisterType<TestValueType>();

Barotrauma/BarotraumaTest/LuaCs/LuaCsFixture.cs

@@ -15,7 +15,7 @@ namespace TestProject.LuaCs
     {
         public LuaCsFixture()
         {
-            LuaCs.ExceptionHandler = (ex, _) =>
+            LuaCsLogger.ExceptionHandler = (ex, _) =>
             {
                 // Pretend we never caught the exception in the first place
                 // (this allows us to preserve the stack trace)