OSOE-682: Upgrading Lombiq.HelpfulLibraries to OrchardCore 1.7

[Psichorex]

OSOE-682

[Piedone]

Remove these:

    /// <summary>
    /// Gets the given content item's display URL.
    /// </summary>
    [Obsolete($"Use {nameof(GetItemDisplayUrl)} instead as this method does not need to be async.")]
    public static Task<string> GetItemDisplayUrlAsync(this IOrchardHelper orchardHelper, ContentItem contentItem) =>
        Task.FromResult(orchardHelper.GetItemDisplayUrl(contentItem));

    /// <summary>
    /// Gets the given content item's display URL.
    /// </summary>
    [SuppressMessage("Design", "CA1055:URI-like return values should not be strings", Justification = "It only returns relative URL.")]
    public static string GetItemDisplayUrl(this IOrchardHelper orchardHelper, ContentItem contentItem) =>
        orchardHelper.GetItemDisplayUrl(contentItem?.ContentItemId);