Allow Multilib in override_apex

Test: m nothing --no-skip-soong-tests
Test: go test apex_text.go
Bug: 246854990
Change-Id: Id6e31c63acd87466a4436288d550ce6b298c677d
diff --git a/apex/apex.go b/apex/apex.go
index bc91407..8d2979e 100644
--- a/apex/apex.go
+++ b/apex/apex.go
@@ -358,6 +358,8 @@
 	// be removed from PRODUCT_PACKAGES.
 	Overrides []string
 
+	Multilib apexMultilibProperties
+
 	// Logging parent value.
 	Logging_parent string