[Console] Fix incorrect output message when status code is 200 and bo…

…dy is empty (elastic#199975)

src/plugins/console/public/application/hooks/use_send_current_request/send_request.ts

@@ -157,10 +157,18 @@ export function sendRequest(args: RequestArgs): Promise<RequestResult[]> {
 
         const { statusCode, statusText } = extractStatusCodeAndText(response, path);
 
-        if (body) {
-          value = JSON.stringify(body, null, 2);
+        // When the request is sent, the HTTP library tries to parse the response body as JSON.
+        // However, if the response body is empty or not in valid JSON format, it throws an error.
+        // To handle this, if the request resolves with a 200 status code but has an empty or invalid body,
+        // we should still display a success message to the user.
+        if (statusCode === 200 && body === null) {
+          value = 'OK';
         } else {
-          value = 'Request failed to get to the server (status code: ' + statusCode + ')';
+          if (body) {
+            value = JSON.stringify(body, null, 2);
+          } else {
+            value = 'Request failed to get to the server (status code: ' + statusCode + ')';
+          }
         }
 
         if (isMultiRequest) {

test/functional/apps/console/_console.ts

@@ -223,5 +223,21 @@ export default function ({ getService, getPageObjects }: FtrProviderContext) {
         expect(await PageObjects.console.hasSuccessBadge()).to.be(true);
       });
     });
+
+    it('Shows OK when status code is 200 but body is empty', async () => {
+      await PageObjects.console.clearEditorText();
+
+      // This request will return 200 but with an empty body
+      await PageObjects.console.enterText(
+        'POST /_cluster/voting_config_exclusions?node_names=node'
+      );
+      await PageObjects.console.clickPlay();
+
+      await retry.try(async () => {
+        const actualResponse = await PageObjects.console.getOutputText();
+        log.debug(actualResponse);
+        expect(actualResponse).to.contain('OK');
+      });
+    });
   });
 }