fix(connectHits): use optional chaining for results.hits length check

[Wcdaren]

Summary

When I use searchkit, even if I report a fixed format containing hits, I still encounter this situation where hits are missing. Therefore, I think a judgment can be added here

Result

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Sandbox	Source
example-instantsearch-getting-started	Configuration
example-react-instantsearch-getting-started	Configuration
example-react-instantsearch-next-app-dir-example	Configuration
example-react-instantsearch-next-routing-example	Configuration
example-vue-instantsearch-getting-started	Configuration

[Haroenv]

can you add a PR to search kit to ensure an empty hits is always returned? this matches the guarantees of the search method