[buildbucket] simplify the if condition for createdBy
[buildbucket] simplify the if condition for createdBy

Change-Id: I966fa2cb25089fb74d47a9f9534f041b6626a9c9
Reviewed-on: https://chromium-review.googlesource.com/c/infra/luci/luci-go/+/2310815
Reviewed-by: Nodir Turakulov <ef4933a197ef7b4b3f55f1bec4942aead3637a2a@chromium.org>
Commit-Queue: Yuanjun Huang <a5f4b8445ce5e958d19c0a7caeadcd07c9d18770@google.com>

luci/luci-go,luci/luci-go,luci/luci-go,luci/luci-go,luci/luci-go,luci/luci-go