Fix UOE issue for immutable collection

As updateOverlaysForTarget returns an immutable collection,
which could cause UnsupportedOperationException when calling
CollectionUtils.addAll.

Test: Manual
Flag: EXEMPT bugfix

Signed-off-by: liulvping <liulvping@xiaomi.corp-partner.google.com>
(cherry picked from https://android-review.googlesource.com/q/commit:a376480af1e76a642e17de4f41c80b6d8483fc85)
Merged-In: I6190f24a9bd5b5f2fed55953101036f9cb3e8ebc
Change-Id: I6190f24a9bd5b5f2fed55953101036f9cb3e8ebc