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.
/assign_reviewer @mercurial.review
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