Switch to HexEncoding from ByteStringUtils

Migration in preparation for deletion of ByteStringUtils.

Bug: 124232146
Test: build only
Change-Id: Iff3a6b11adb8bcc51417a2e96e42c2db8a2de257
(cherry picked from commit 6f34427eb209a1c2b341c3aea034f46337308696)
1 file changed