message: fix: correctly find Config.class on old version of Optifine
diff: @@ -81,7 +81,8 @@ export function installByInstallerTask(installer: string, minecraft: MinecraftLo
  let zip = await open(installer);
  context.update(10, 100);
  - let entry = zip.entries["net/optifine/Config.class"];
  + let entry = zip.entries["net/optifine/Config.class"]
  + ?? zip.entries["Config.class"];
  if (!entry) {
  throw createErr({ error: "BadOptifineJar", entry: "net/optifine/Config.class" });
  }
  