Since R06:M-5 the Sparkplug browser states no address for a metric the
ingestor will not read and labels its descriptor 'not bindable', but the commit
refusal still said the attribute lookup returned nothing. RawBrowseModal keeps
the attribute's descriptor on the selection, and DescribeUncommittableLeaf
reports a 'cannot be bound in this version' message echoing it. A lookup that
really returned nothing keeps the old text. A test pins the marker to the
browser's own string.
Refs #745
Claude-Session: https://claude.ai/code/session_01Ub9hGmYLQvn9XETzw7CMsT
Joseph Doherty
15bd409cdd