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

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

MUST ONLY BE SUBMITTED BY AUTOMERGER

Change-Id: I5ce4bb83b89f2901fee5652c6ea0897dadd14ba2