[antlir] Expose another prelude select function

Summary: As title

Test Plan: CI

Reviewed By: vmagro

Differential Revision: D94238241

fbshipit-source-id: 9bd2e4ac9e266ee82379078db250b565d8ec193a

Author: get9

antlir/antlir2/bzl/selects.bzl

@@ -74,6 +74,7 @@ def _or(branches):
 
 selects = struct(
     apply = _prelude_selects.apply,
+    apply_n = _prelude_selects.apply_n,
     join = _join,
     or_ = _or,
     test_any_of = _test_any_of,