Normalize a raw propType string to a canonical DfsPropTypeKey when
we recognise it; otherwise return the input cleaned of leading/
trailing whitespace. Unknown variants are intentionally preserved
verbatim so display-side code still has something to render — the
adapter is the gatekeeper that decides whether a string is gradable.
Normalize a raw propType string to a canonical DfsPropTypeKey when we recognise it; otherwise return the input cleaned of leading/ trailing whitespace. Unknown variants are intentionally preserved verbatim so display-side code still has something to render — the adapter is the gatekeeper that decides whether a string is gradable.