conda_vendor --refresh-pins stays silent when the pinned release lost a wheel #2028

Describe the bug
util/conda_vendor.py refresh() still makes no note when the newest release with a wheel for every conda Python is older than the pin, i.e. the pinned release itself has lost a wheel. The pin stays as it is, and --refresh-pins passes silently. #2026 fixes the related case where no release qualifies at all, and deliberately leaves this one out.

Reproduction
Reading refresh() at #2026's head: the branch newest is not None and target is None covers both "the pin is still the newest" (correct, silent) and newest < pin.version (stuck, silent).

Expected behavior
A ::warning that names the pin and the newest release that still qualifies, with the step still passing, as #2026 does for the no-release case.

System information

• commit: fix(ci): warn when --refresh-pins cannot move a pin (#2025) #2026 head b12821ccb

Additional context
Raised in #2026's cross-review. It touches the same function, so it waits for #2026 to land.