Gets the ICC profile of the output condition (DestOutputProfile) as an ICCBased colour space, or null
when the dictionary has none.
public PdfIccBasedColorSpace? DestinationProfile { get; }
ISO 32000-2 Table 401: "the same format as that used in specifying an ICCBased colour space" (§8.6.5.5), so the stream is read
as one, with the repairs and diagnostics of PdfIccBasedColorSpace; its alternate is the device space with as many
components. A value that is not a stream reads as missing with an OutputIntentInvalid diagnostic. The same space is
returned until the entry changes.