Former President Donald Trump continues to lead the pack in the Des Moines Register/NBC News/Mediacom Iowa Poll released Saturday, but his lead has dropped by a few percentage points since December. The poll also showed former U.N. Ambassador Nikki Haley has moved into second place, ahead of Florida Gov. Ron DeSantis for the first time in the Iowa Poll. The survey of likely Iowa Republican caucusgoers found 48% pick Trump as their first choice candidate, followed by Haley at 20% and DeSantis at 16%. Trump and DeSantis both fell by 3 percentage points from the December poll, when the former pre…