21381d843f
## Description This PR makes DropdownMenu rematching the initialSelection when the entries are updated. If the new entries contains one entry whose value matches `initialSelection` this entry's label is used to initialize the inner text field, if no entries matches `initialSelection` the text field is emptied. ## Related Issue Fixes [DropdownMenu.didUpdateWidget should re-match initialSelection when dropdownMenuEntries have changed](https://github.com/flutter/flutter/issues/155660). ## Tests Adds 3 tests.