tr2/demo: restore config caching on demo start

Resolves #2574.

docs/tr2/CHANGELOG.md

@@ -10,6 +10,7 @@
 - fixed missing new game text in the passport when play any level is enabled (#2563, regression from 0.9)
 - fixed the play any level dialog not showing in the gym passport (#2564, regression from 0.9)
 - fixed losing the NG+ flag when loading a save that has it set (#2566, regression from 0.9.2)
+- fixed the ammo counter not showing in demos if NG+ is set (#2574, regression from 0.9)
 
 ## [0.9.2](https://github.com/LostArtefacts/TRX/compare/tr2-0.9.1...tr2-0.9.2) - 2025-02-19
 - fixed secret rewards not handed out after loading a save (#2528, regression from 0.8)

src/tr2/game/demo.c

@@ -125,6 +125,8 @@ bool Demo_Start(const int32_t level_num)
     ASSERT(p->level != nullptr);
     ASSERT(GF_GetCurrentLevel() == p->level);
 
+    M_PrepareConfig(p);
+
     const uint32_t *const data = Demo_GetData();
     if (data == nullptr) {
         LOG_ERROR("Level '%s' has no demo data", p->level->path);