fix: unique key warning on componentized element

[rothsandro]

Fixes the unique key warning that occurs with React 19 when the Trans component was used with elements with children. The created Componentized element didn't include the original key.

Fixes #1834

Checklist

• only relevant code is changed (make a diff before you submit the PR)
• run tests npm run test
• tests are included
• commit message and code follows the Developer's Certification of Origin

Checklist (for documentation change)

• only relevant documentation part is changed (make a diff before you submit the PR)
• motivation/reason is provided
• commit message and code follows the Developer's Certification of Origin

[coveralls]

coverage: 95.797%. remained the same
when pulling 8250d5d on rothsandro:bugfix/componentized-key
into 330a8e7 on i18next:master.

[adrai]

included in v15.4.1
thx for your contribution