Update unicode-segmentation to 1.9.0 am: 0135332a11 am: 4760cd2814 am: 67985a2aa8 am: ca6c3ad74a

Original change: https://android-review.googlesource.com/c/platform/external/rust/crates/unicode-segmentation/+/2004739

Change-Id: Ia2b7c95849eb08d8047e1b6091b778be9b01b4c1