handling of unknown keys in the block code

[u-fischer]

An unknown key on an itemize environment error but is silently ignored e.g. on a quote:

\DocumentMetadata{}
\documentclass{article}
\begin{document}
\begin{quote}[unknownkey=bla]
a
\end{quote}

\begin{itemize}[unknownkey=bla]
\item a
\end{itemize}

\end{document}

! Package block Error: Some keys specified on the itemize environment are
(block)                unknown.

Perhaps the test for unused keys should better be done in \BlockEnvEnd?