Restore RcppArmadillo header in RcppExports.cpp

Co-authored-by: osorensen <21175639+osorensen@users.noreply.github.com>

Author: Copilot

src/RcppExports.cpp

@@ -1,6 +1,7 @@
 // Generated by using Rcpp::compileAttributes() -> do not edit by hand
 // Generator token: 10BE3573-1514-4C36-9D1C-5A225CD40393
 
+#include <RcppArmadillo.h>
 #include <Rcpp.h>
 
 using namespace Rcpp;