[resultdb] Print invocation id
[resultdb] Print invocation id

It is inconsistent to accept invocation IDs, but print invocation names.
Reserve invocation names for APIs. In CLI, converge on IDs.

R=9e0728822fdb2ce07b011b42510312bb837e6a51@chromium.org

Change-Id: I03d6aec739f896a2321e86f21842d000011591d1
Reviewed-on: https://chromium-review.googlesource.com/c/infra/luci/luci-go/+/2177105
Commit-Queue: Erik Staab <9e0728822fdb2ce07b011b42510312bb837e6a51@chromium.org>
Reviewed-by: Erik Staab <9e0728822fdb2ce07b011b42510312bb837e6a51@chromium.org>
Auto-Submit: Nodir Turakulov <ef4933a197ef7b4b3f55f1bec4942aead3637a2a@chromium.org>

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