Bruno Leroux 0adb0337e0
Deprecate DropdownButtonFormField "value" parameter in favor of "initialValue" (#170805)
## Description

This PR renames the DropdownButtonFormField constuctor parameter 'value'
to 'initialValue'.
See
https://github.com/flutter/flutter/pull/170050#issuecomment-2965486000
and
https://github.com/flutter/flutter/pull/170050#issuecomment-2971920009
for some context.

## Related Issue

Fixes [DropdownButtonFormField retains selected value even after setting
value to null](https://github.com/flutter/flutter/issues/169983#top)

## Tests

Adds 2 tests (one to validate the deprecated parameter can still be
used, one for the dart fix).
Updates many (renaming the confusing parameter).
2025-06-24 07:08:21 +00:00
..