Multi-tenancy: sharing grants stay within the owner's tenant (MT-1, MT-3)

JMAP shareWith refuses a grantee outside the owner's tenant, or missing, with
invalidForeignKey naming the account. WebDAV ACL answers AllowedPrincipal and
IMAP SETACL answers as for an unknown account.

crates/jmap/src/file/copy.rs

@@ -370,7 +370,7 @@ impl FileNodeCopy for Server {
             }
 
             if !file_node.acls.is_empty() {
-                if let Err(err) = self.acl_validate(&file_node.acls).await {
+                if let Err(err) = self.acl_validate(account_id, &file_node.acls).await {
                     response.not_created.append(id, err.into());
                     continue 'create;
                 }