Fix the mvexpand doctest

Signed-off-by: Srikanth Padakanti <srikanth_padakanti@apple.com>

Author: srikanthpadakanti

docs/user/ppl/cmd/mvexpand.md

@@ -118,7 +118,7 @@ fetched rows / total rows = 1/1
 ```
 
 ### Example 5: Missing Field
-If the field does not exist in the input schema (for example, it is not mapped or was projected out earlier), mvexpand does not throw an error and produces no rows.
+If the field does not exist in the input schema (for example, it is not mapped or was projected out earlier), mvexpand throws a semantic check exception.
 
 PPL query:
 ```ppl
@@ -132,11 +132,8 @@ source=people
 
 Expected output:
 ```text
-fetched rows / total rows = 0/0
-+------+
-| tags |
-|------|
-+------+
+{'reason': 'Invalid Query', 'details': "Field 'tags' not found in the schema", 'type': 'SemanticCheckException'}
+Error: Query returned no data
 ```
 
 ## Notes about these doctests

integ-test/src/test/java/org/opensearch/sql/ppl/NewAddedCommandsIT.java

@@ -217,11 +217,11 @@ public void testTransposeCommand() throws IOException {
   public void testMvExpandCommand() throws IOException {
     JSONObject result;
     try {
-      executeQuery(String.format("search source=%s | mvexpand address", TEST_INDEX_BANK));
+      result = executeQuery(String.format("search source=%s | mvexpand address", TEST_INDEX_BANK));
     } catch (ResponseException e) {
       result = new JSONObject(TestUtils.getResponseBody(e.getResponse()));
-      verifyQuery(result);
     }
+    verifyQuery(result);
   }
 
   private void verifyQuery(JSONObject result) throws IOException {