Add Hexagon (Victor) shape to icon shape overlay (will show up in custom options)

https://screenshot.googleplex.com/4Ta8OOrfJpV

Bug: 150234338
Test: installed the apk and then changed it in custom style options
$ adb install out/target/product/generic/system/product/overlay/IconShapeHexagon/IconShapeHexagonOverlay.apk

Change-Id: I9f0848d772bdaaacaa6cc2e30bc6e992f323f974