Include TARGET_ODM_PROP to odm/etc/build.prop

It's missing in Soong's build_prop module.

Bug: 322090587
Bug: 361623560
Test: set TARGET_ODM_PROP and see odm/etc/build.prop
Change-Id: I447a64998f6ae0ba80201ab4ab6c0fd0ef22e3e5
diff --git a/android/config.go b/android/config.go
index 77c5b34..fc397f4 100644
--- a/android/config.go
+++ b/android/config.go
@@ -2057,6 +2057,10 @@
 	return PathsForSource(ctx, c.productVariables.ProductPropFiles)
 }
 
+func (c *config) OdmPropFiles(ctx PathContext) Paths {
+	return PathsForSource(ctx, c.productVariables.OdmPropFiles)
+}
+
 func (c *config) EnableUffdGc() string {
 	return String(c.productVariables.EnableUffdGc)
 }