Fix duplicated wrap text and break text translation contexts

[jacek-cke]

🚀 Summary

Move shared "Wrap text" and "Break text" translation contexts to core.

The new media embed alignment feature reuses the "Wrap text" and "Break text" source strings already declared by ckeditor5-image, which made translations:validate fail with a "Duplicated context" error. Since the validator only accepts a context from the message's own package or from ckeditor5-core, the keys are moved to the core package.

🧾 Checklists

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Author checklist

• Is the changelog entry intentionally omitted?
• Is the change backward-compatible?
• Have you considered the impact on different editor setups and core interactions? (e.g., classic/inline/multi-root/many editors, typing, selection, paste, tables, lists, images, collaboration, pagination)
• Has the change been manually verified in the relevant setups?
• Does this change affect any of the above?
• Is performance impacted?
• Is accessibility affected?
• Have tests been added that fail without this change (against regression)?
• Have the API documentation, guides, feature digest, and related feature sections been updated where needed?
• Have metadata files (ckeditor5-metadata.json) been updated if needed?
• Are there any changes the team should be informed about (e.g. architectural, difficult to revert in future versions or having impact on other features)?
• Were these changes documented (in Logbook)?

Reviewer checklist

• PR description explains the changes and the chosen approach (especially when performance, API, or UX is affected).
• The changelog entry is clear, user‑ or integrator-facing, and it describes any breaking changes.
• All new external dependencies have been approved and mentioned in LICENSE.md (if any).
• All human-readable, translateable strings in this PR been introduced using t() (if any).
• I manually verified the change (e.g., in manual tests or documentation).
• The target branch is correct.

[pomek]

Could we please also move existing translations to avoid generating additional costs?

See: https://www.notion.so/Internationalization-a-developer-perspective-f27a39c4ec234fe98b5aab5fad5269fa?source=copy_link#26bbb9a67232805aa1f3cb7061c24bf6.