Access invalid option from the `InvalidFilter` instance

Background

With UI#228 UI team would like to introduce also hints for invalid filter options, see example in screenshot:

In order to achieve that, would be great to make first matched invalid option be available from InvalidFilter object instance.

What to change

Make invalid filter option accessible from InvalidFilter instance, i.e.:

const filter = Filter.fromText("@@||example.com^$foo");
if (filter instanceof InvalidFilter && filter.reason === "filter_unknown_option")
{
  console.log(filter.option); // foo
}

Testing

Testing this is covered by the unit tests.

To test this manually, try to create a filter with an unknown option with Filter.fromText(), and it will return an invalid filter, and the option property will be set to that unknown option.