400: Invalid label name - invalidArgument for multiple labels

Hi, when I try to recover I have this error.

```
Creating label Da leggere
400: Invalid label name - invalidArgument
```

I tried

`--extra-reserved-labels "da leggere"`

But now I get

```
leggereg label Da
400: Invalid label name - invalidArgument
```

How cat I solve? Can I pass multiple reserved labels?

Start at the CLI handling for --extra-reserved-labels and reproduce the recovery command with a label containing spaces and with multiple labels. Trace how the argument is split before labels are created; done means multiple reserved labels, including spaced names, are accepted without the Gmail invalidArgument error.

Written by the indexing model from the issue text.