Add code comments in ValidateConnectionBindingCompleteness explaining
that the unbound-attribute branch also covers the silently-dropped
stale-binding case (cross-reference FlatteningService.ApplyConnectionBindings),
and that the `continue` skips the exists-at-site check for unbound attrs.
Add two new tests:
- FlatteningPipelineConnectionBindingTests: stale DataConnectionId (999)
not present in site connections → flattener drops it silently →
validator reports ConnectionBinding Error, IsValid false.
- ValidationServiceTests: enforce:true + siteConnectionNames:null on a
properly-bound attribute → no ConnectionBinding error (exists-at-site
check stays inert when site set is not supplied).
Joseph Doherty
21b801b71f