operations: fix lsjson --encrypted when using --crypt-XXX parameters

Before this change an `rclone lsjson --encrypted` command where
additional `--crypt-` parameters were supplied on the command line:

    rclone lsjson --crypt-description XXX --encrypted secret:

Produced an error like this:

    Failed to lsjson: ListJSON failed to load config for crypt remote: config name contains invalid characters...

This was due to an incorrect lookup of the crypt config to create the
encrypted mapping.

Fixes #7833

fs/operations/lsjson.go

@@ -119,7 +119,7 @@ func newListJSON(ctx context.Context, fsrc fs.Fs, remote string, opt *ListJSONOp
 		lj.dirs = false
 	}
 	if opt.ShowEncrypted {
-		fsInfo, _, _, config, err := fs.ConfigFs(fsrc.Name() + ":" + fsrc.Root())
+		fsInfo, _, _, config, err := fs.ConfigFs(fs.ConfigStringFull(fsrc))
 		if err != nil {
 			return nil, fmt.Errorf("ListJSON failed to load config for crypt remote: %w", err)
 		}