[cherry-pick][6.10] fix: restore JEXL allowlist explanation in error message

wrangler-core/src/main/java/io/cdap/wrangler/expression/EL.java

@@ -198,10 +198,16 @@ private static ELException handleJexlException(
         detail, line, column);
 
     if (isJexlPermissionViolation(e, allowlistEnabled)) {
-      throw new ELPermissionException(baseErrorMessage, e);
+      throw new ELPermissionException(
+          String.format(
+              "%s Make sure the JEXL transformation is valid and uses only allowlisted classes, "
+                  + "methods, and properties.",
+              baseErrorMessage),
+          e);
     }
 
-    return new ELException(baseErrorMessage, e);
+    return new ELException(
+        String.format("%s Make sure the JEXL transformation is valid.", baseErrorMessage), e);
   }
 
   private static boolean isJexlPermissionViolation(JexlException e, boolean allowlistEnabled) {

wrangler-core/src/test/java/io/cdap/wrangler/executor/RecipePipelineExecutorTest.java

@@ -121,6 +121,11 @@ public void testELPermissionExceptionFailsOnFirstRow() throws Exception {
       Assert.assertEquals(0, e.getRowIndex());
       Assert.assertEquals(1, e.getDirectiveIndex());
       Assert.assertTrue(e.getCause() instanceof ELPermissionException);
+      Assert.assertTrue(
+          e.getMessage()
+              .contains(
+                  "Make sure the JEXL transformation is valid and uses only allowlisted classes, "
+                      + "methods, and properties."));
       Assert.assertTrue(pipeline.errors().isEmpty());
     }
   }