Update package:intl4x to 1.0.0-alpha.1 for Dart

[mosuem]

No description provided.

[gemini-code-assist]

Code Review

This pull request updates the Dart SDK environment constraint to ^3.12.0 and upgrades several dependencies in pubspec.yaml and pubspec.lock. It also attempts to change how dateStyle and timeStyle are added to the options map in datetime_format.dart. However, the introduced syntax 'dateStyle': ?dateStyle is invalid in Dart and will cause a compilation error. It is recommended to revert to the original collection-if syntax (if (dateStyle != null)) to conditionally include these keys.

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[gemini-code-assist]

The syntax 'dateStyle': ?dateStyle is invalid in Dart and will cause a compilation error. Dart does not support the ? prefix operator for map values or entries. If you want to conditionally include these keys only when they are non-null (consistent with yearStyle and calendar below), you should use the if (variable != null) collection-if syntax. If you want to always include the keys (even with null values), simply use dateStyle and timeStyle without the ? prefix.

Suggested change

	'dateStyle': ?dateStyle,
	'timeStyle': ?timeStyle,
	if (dateStyle != null) 'dateStyle': dateStyle,
	if (timeStyle != null) 'timeStyle': timeStyle,