bugfix: incorrect error return in applyClientOptions function

[0xd219b]

This commit corrects an errors handling issue in the applyClientOptions function within the opensearch options module.

Previously, when the opensearch client was missing, the function erroneously returned ErrMissingEmbedded instead of ErrMissingOpensearchClient.

This update ensures that the current error is returned.

PR Checklist

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• [x] Name your Pull Request title clearly, concisely, and prefixed with the name of the primarily affected package you changed according to Good commit messages (such as memory: add interfaces for X, Y or util: add whizzbang helpers).
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• [x] Provide a description in this PR that addresses what the PR is solving, or reference the issue that it solves (e.g. Fixes #123).
• [x] Describes the source of new concepts.
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• [] Contains test coverage for new functions.
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