*_timezone changes also affect the BirthdayType
minor #12494 [Form] *_timezone changes also affect the BirthdayType (xabbuh)

This PR was merged into the 2.6 branch.

Discussion
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[Form] *_timezone changes also affect the BirthdayType

| Q             | A
| ------------- | ---
| Fixed tickets |
| License       | MIT

The changes from #12404 also affect the `BirthdayType`.

Commits
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7faee60 *_timezone changes also affect the BirthdayType