phases: leverage the collected information to record phase update
Since the lower level function already gather this information, we can directly
use it.
This comes with a small change to the test that are actually fixing them. The
previous version over-reported some phase change that did not exists. In both
case, we are force revision `1` to be secret and `0` remains draft`, the
previous code wrongly reported `0` as moving to secret while it properly
remained draft in the repository.
{
"conduit_uri": "https://phab.mercurial-scm.org/api",
"phabricator.uri": "https://phab.mercurial-scm.org/",
"repository.callsign": "HG",
"arc.land.onto.default": "@",
"base": "hg:.^"
}