Witney Carson just made one of Dancing With the Stars’ biggest announcements Monday, as it was revealed that she is pregnant and still returning as a professional dancer on the show for season 35. “I feel like I’ve been keeping a dark, dirty secret for a really, really long time,” the two-time mirrorball champion tells The Hollywood Reporter of how she’s feeling about the news being out for the public. Her answer is a reference to a month of speculation that she was expecting her third child with husband Carson McAllister. Because of the rumors, fans thought this meant Carson was bowing out for season 35, but that is not the case. She is…