[LSC] Add LOCAL_LICENSE_KINDS to external/libwebm am: a26f3396c1 am: db06ddaca6 am: 1e39c29b88 am: e0cd8697cf

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

MUST ONLY BE SUBMITTED BY AUTOMERGER

Change-Id: I39fc7213cb10af4970c708c8a42650e70b83b46c