Use the PYROGENESIS_VERSION macro instead of a global

Reviewed-At: https://gitea.wildfiregames.com/0ad/0ad/pulls/8222

source/ps/scripting/JSInterface_Mod.cpp

@@ -135,7 +135,7 @@ JS::Value GetEngineInfo(const ScriptInterface& scriptInterface)
 	Script::CreateObject(
 		 rq,
 		 &metainfo,
-		 "engine_version", engine_version,
+		 "engine_version", PYROGENESIS_VERSION,
 		 "mods", mods);
 
 	Script::DeepFreezeObject(rq, metainfo);