Remove the flag that lets a run report skips as acceptable

[estebanzimanyi]

--allow-skips made the rule conditional: a repository passing it reported
success over a suite that asserted nothing, and the summary line said so in
words that read like a pass. No workflow in the ecosystem passes it — a code
search over MEOS-API, GoMEOS, JMEOS, MobilityAPI, MobilityFlink, MobilitySpark,
MobilityKafka, MobilityDuck and PyMEOS finds the flag only in this file's own
definition, and the composite action never exposed it — so it stands as an
escape hatch and nothing else. The parser now rejects it:
unrecognized arguments: --allow-skips.

The command line moves into build_parser so the suite can read its options,
and two tests keep the hatch shut. One asserts that no option carries skip or
ignore in its name, against a positive control that --min-tests is there, so
the assertion cannot pass over a parser it failed to build. The other reads a
vstest summary carrying one skip and holds that the count reaches the caller
whatever the floor says.

18 tests pass. Against a real dotnet test log the tool exits 0 on a clean run,
1 on a summary carrying Skipped: 1, 1 on a floor above the total, and 2 on the
removed flag.