"[I]n a declaratory judgment action where the trial court decides questions of fact, we review the challenged findings of fact and determine whether they are supported by competent evidence. If we determine that the challenged findings are supported by competent evidence, they are conclusive on appeal. We review the trial court's conclusions of law de novo. Calhoun v. WHA Med. Clinic, PLLC, 178 N.C. App. 585, 596-97, 632 S.E.2d 563, 571 (2006) (citations omitted), disc. review denied, 361 N.C. 350, 644 S.E.2d 5 (2007).