Fix $eval call to evaluate. #58

Call internal evaluate that does not reset the context

src/main/java/com/dashjoin/jsonata/Functions.java

@@ -2389,7 +2389,7 @@ public static Object functionEval(String expr, Object focus) {
         }
         Object result = null;
         try {
-            result = ast.evaluate(input, env);
+            result = Jsonata.current.get().evaluate(ast.ast, input, env);
         } catch(Throwable err) {
             // error evaluating the expression passed to $eval
             //populateMessage(err);

src/test/java/com/dashjoin/jsonata/CustomFunctionTest.java

@@ -24,7 +24,6 @@ public void testEval() {
     Assertions.assertEquals("Hello world", expression.evaluate(null));
   }
 
-  @Disabled
   @Test
   public void testEvalWithParams() {
     var expression = Jsonata.jsonata("($eval('$greet()'))");