Fix #5285. Config file not read correctly.

When the hashing function finds a collision such as on play_intro and auto_staff_placement it has to do a string compare to find out if two map entries are different. Due to a mistype this comparison would always return true. This meant that the auto_staff_placement value would overwrite the play_intro value. Mistake caused when fixing previous bug

src/openrct2/config/IniReader.cpp

@@ -84,7 +84,7 @@ struct StringICmp
         for (std::size_t i = a.size(); i > 0; --i, ++s1, ++s2)
         {
             const int c1 = std::toupper(Traits::to_int_type(*s1));
-            const int c2 = std::toupper(Traits::to_int_type(*s1));
+            const int c2 = std::toupper(Traits::to_int_type(*s2));
             if (c1 != c2) return false;
         }
         return true;