The overflow menu ("...") showed "Forward as attachment" whenever the
handler was provided, regardless of whether the open email has a
blobId. If it doesn't, handleForwardAsAttachment immediately no-ops
(buildForwardAsAttachmentPayload returns null), so the item was
clickable but did nothing - inconsistent with the list context menu's
version, which is already disabled in that case
(!onForwardAsAttachment || !email.blobId).
Gate both occurrences (desktop and mobile layouts) on email?.blobId
too, matching the context menu's behavior.
Caught by GitHub Copilot's automated PR review.