Change final stretch song to Piercing the Sky

After the dimension destabilizes, the song that plays is Positive Force.
Which has already been played twice in the game at that point (first in
Tower, then in the Gravitron). Since Piercing the Sky is unused, why not
play a song that the player hasn't heard before? It would also be
musically fitting for the scenario.

The song gets played in two places - one for if you have cutscenes
enabled, and one for if you don't - so we just need to change both of
them.

I asked Terry in Discord DMs if he wanted this change and he approved of
it.

desktop_version/src/Game.cpp

@@ -1472,7 +1472,7 @@ void Game::updatestate(void)
             //Init final stretch
             state++;
             music.playef(9);
-            music.play(2);
+            music.play(14);
             obj.flags[72] = true;
 
             screenshake = 10;

desktop_version/src/TerminalScripts.cpp

@@ -434,7 +434,7 @@ void scriptclass::loadother(const char* t)
         "speak_active",
         "endtext",
 
-        "play(2)",
+        "play(14)",
         "changemood(player,0)",
 
         "endcutscene()",