[Ownership] Assign test files to shared ux team (elastic#201988)

## Summary

Assign test files to shared ux team

Contributes to: elastic#192979

.github/CODEOWNERS

@@ -2498,6 +2498,7 @@ x-pack/test/profiling_api_integration @elastic/obs-ux-infra_services-team
 x-pack/plugins/observability_solution/observability_shared/public/components/profiling @elastic/obs-ux-infra_services-team
 
 # Shared UX
+/x-pack/test_serverless/api_integration/test_suites/common/favorites @elastic/appex-sharedux # Assigned per https://github.com/elastic/kibana/pull/200985
 /test/api_integration/apis/short_url/**/*.ts @elastic/appex-sharedux # Assigned per https://github.com/elastic/kibana/pull/200209/files#r1846654156
 /test/functional/page_objects/share_page.ts @elastic/appex-sharedux # Assigned per https://github.com/elastic/kibana/pull/200209/files#r1846648444
 /test/accessibility/apps/kibana_overview_* @elastic/appex-sharedux # Assigned per https://github.com/elastic/kibana/pull/200209/files/cab99bce5ac2082fa77222beebe3b61ff836b94b#r1846659920