validate method
Validates the provided value against the field's constraints. Returns a list of validation error messages. @param value is the value to validate @returns a list of validation error messages, empty if valid
Implementation
Future<List<String>> validate(dynamic value) async {
var results = <String>[];
for (var validator in validators) {
var result = await validator(value);
if (result.isNotEmpty) {
results.add(result);
}
}
return results;
}