Fix class cast issue in AddItemActivity am: 671ffb88ca am: 02c75d9897 am: 7bea9de0b3

Original change: https://googleplex-android-review.googlesource.com/c/platform/packages/apps/Launcher3/+/15299573

Change-Id: I7db9f4b507bf64e834b062d889e159d14627c42b