Skip failing serverless discover and visualize tests for MKI (elastic…

…#191239)

## Summary

This PR skips the failing serverless discover and visualize tests for
MKI runs.

For more details, see the corresponding issues elastic#191237 and elastic#191238.

x-pack/test_serverless/functional/test_suites/common/context/_discover_navigation.ts

@@ -35,7 +35,10 @@ export default function ({ getService, getPageObjects }: FtrProviderContext) {
   const browser = getService('browser');
   const kibanaServer = getService('kibanaServer');
 
-  describe('context link in discover', () => {
+  describe('context link in discover', function () {
+    // flaky on MKI, see https://github.com/elastic/kibana/issues/191237
+    this.tags(['failsOnMKI']);
+
     before(async () => {
       await PageObjects.timePicker.setDefaultAbsoluteRangeViaUiSettings();
       await kibanaServer.uiSettings.update({

x-pack/test_serverless/functional/test_suites/common/visualizations/group2/open_in_lens/agg_based/goal.ts

@@ -21,6 +21,9 @@ export default function ({ getPageObjects, getService }: FtrProviderContext) {
   const kibanaServer = getService('kibanaServer');
 
   describe('Goal', function describeIndexTests() {
+    // fails on MKI, see https://github.com/elastic/kibana/issues/191238
+    this.tags(['failsOnMKI']);
+
     const fixture =
       'x-pack/test_serverless/functional/fixtures/kbn_archiver/lens/open_in_lens/agg_based/goal.json';