Fix: update spread operator handling to use addIfExpr (#226)

Author: cesarParra

expression-src/main/src/interpreter/Parser.cls

@@ -183,7 +183,7 @@ public with sharing class Parser {
     private Expr spread() {
         if (match(TokenType.SPREAD)) {
             Token spreadToken = previous();
-            Expr right = getExpr();
+            Expr right = addIfExpr();
             return new Expr.Spread(
                 spreadToken,
                 right