keybase1: emulate legacy SigIDBase export (#22911)
keybase1: emulate legacy SigIDBase export (#22911)

- always output 0x0f suffix in case client needs to downgrade
keybase/client,keybase/client,keybase/client,keybase/client,keybase/client,keybase/client,keybase/client,keybase/client,keybase/client,keybase/client,keybase/client,keybase/client