[LSC] Add LOCAL_LICENSE_KINDS to external/libwebm am: a26f3396c1 am: db06ddaca6 am: 1e39c29b88

Original change: https://android-review.googlesource.com/c/platform/external/libwebm/+/1588663

MUST ONLY BE SUBMITTED BY AUTOMERGER

Change-Id: Ib4ebe02ddfe6a60a9237f29797ad7a0519e0ada1