Html.UrlLink() extension adds port 25 to email url

Description

Html.UrlLink() extension adds port 25 after email address when rendering an email link on a web page.

Step to reproduce

1. Add a property of type EPiServer.Url to any page type, or block type.

public virtual Url Link { get; set; }

1. Modify its view to render the added property with Html.UrlLink().

@Html.UrlLink(Model.CurrentPage.Link, "This is the link", new Dictionary<string, object>() { { "class", "btn" } })

1. Start the site, go to EPiServer Edit mode and edit the Url property.
2. Set its type to "email", with a sample value, then publish the page.
3. Go to view mode to observe the result.

Expected: The email link is rendered correctly.
Actual: The email link has port 25 placed after the mail address.