Revise ownership of technical documenation

What does this MR do?

This MR updates the .gitlab/CODEOWNERS file to revise ownership of technical documentation by:

• Adding @gitlab-com/localization/maintainers/tech-docs as owners for /doc-locale/ and /argo_translation.yml
• Adding specific ownership for Japanese documentation (/doc-locale/ja-jp/) with both the general tech-docs team and the Japanese-specific team (@gitlab-com/localization/maintainers/tech-docs/ja-jp)

These changes ensure that technical documentation localization files have proper ownership assignment for review and maintenance purposes.

Related issues

Related gitlab-com/localization/localization-team#477 (closed)

Author checklist

For general guidance, please follow our Contributing guide.

Required

For anything in this list which will not be completed, please provide a reason in the MR discussion.

• Merge Request Title and Description are up to date, accurate, and descriptive.
• MR targeting the appropriate branch.
• MR has a green pipeline.
• Documentation created/updated.
• Tests added/updated, and test plan for scenarios not covered by automated tests.
• Equivalent MR/issue for omnibus-gitlab opened. gitlab-org/omnibus-gitlab!9138 (merged)

Reviewers checklist

• MR has a green pipeline on https://gitlab.com/gitlab-org/charts/gitlab.
• Consider downstream impact to the Operator, as per evaluating impact from changes to GitLab chart.