fix recent refactoring regression (#6724)

soh/soh/Enhancements/randomizer/3drando/fill.cpp

@@ -736,7 +736,7 @@ static void PareDownPlaythrough() {
     }
 
     // Some spheres may now be empty, remove these
-    for (size_t i = ctx->playthroughLocations.size() - 2; i >= 0; i--) {
+    for (int32_t i = static_cast<int32_t>(ctx->playthroughLocations.size()) - 2; i >= 0; i--) {
         if (ctx->playthroughLocations.at(i).size() == 0) {
             ctx->playthroughLocations.erase(ctx->playthroughLocations.begin() + i);
         }