Get URL for link labelled X

Feature request

Add a new method that allows the user to specify a link label, of which the method returns the URL that the label is linked to.

e.g. if I have an email with 2 links:

1. `First link`
2. `Second link`

It would be great if we could do something like: `$I->getUrlForLink('Second link')` to get the URL from the second link.

Feel free to make the method name anything you like that makes sense.

No file or test entry point is named in the issue. Start by locating the module's existing email and link-handling APIs, then determine where a label-to-URL lookup belongs. Done means the specified link label returns its linked URL, including the illustrated second-link case, with coverage for the behavior.

Written by the indexing model from the issue text.