fix(core): resolve type mismatch in useGetLocale hook

[arndom]

PR Checklist

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• The commit message follows our guidelines: https://refine.dev/docs/guides-concepts/contributing/#commit-convention

Bugs / Features

• Related issue(s) linked
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What is the current behavior?

useTranslation().getLocale returns string | undefined instead of string.

What is the new behavior?

• useTranslation().getLocale returns a string.
• useGetLocale will throw an error if there is no i18n provider, ensuring a string as the return type of useTranslation().getLocale.

resolves #6812

Notes for reviewers

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🦋 Changeset detected

Latest commit: fefa1ba

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

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@refinedev/core	Patch

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[alicanerdurmaz]

Thanks @arndom, this PR is great, but it's a breaking change. We plan to release a major version next week with this PR. We can include this implementation in Refine v5. What do you think?

[arndom]

@alicanerdurmaz yh, sure, go ahead.