feat: extend default settings in AsyncVectorStore

[minglu7]

This commit introduces a new parameter, custom_settings, to the AsyncVectorStore class. This allows users to provide their own settings that will extend the default settings. This increases the flexibility of the class and allows it to be tailored to specific use cases. The custom settings are applied in the _create_index_if_not_exists method.

[github-actions[bot]]

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[miguelgrinberg]

@minglu7 Thanks for your contribution! I have made a couple of suggested changes for you to consider.

You also need to run nox -rs format to ensure that the change that you've made in the async version of the Vectorstore class is also applied on the synchronous version. Then you will include the changes to both versions in this PR.

Finally, it would be useful if you can add a unit test in test_elasticsearch/test_server/test_vectorstore/test_vectorstore.py.

Thanks, again!

[pquentin]

buildkite test this please

[pquentin]

buildkite test this please

[minglu7]

buildkite test this please

send it again please

[pquentin]

buildkite test this please

[minglu7]

buildkite test this please

check these changed files, please

[pquentin]

buildkite test this please

[miguelgrinberg]

buildkite test this please