[ja] Translate kms-provider.md into Japanese (#51690)

* [ja] Translate kms-provider.md into Japanese

* Remove reviewers field from Japanese translation metadata

* Localize placeholder text and remove legacy hyperlinks in Japanese KMS provider docs

* Fix Japanese localization style guide violations in KMS provider docs

* Refactor KMS provider documentation for clarity and readability

* Improve Japanese language flow and formatting

* Changed notations

* Apply suggestions from code review

Applied suggestions from code review

Co-authored-by: inukai <[email protected]>
Co-authored-by: youmeim <[email protected]>

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Co-authored-by: inukai <[email protected]>
Co-authored-by: youmeim <[email protected]>

Author: 3 people