Handle deprecated API in DatePickerController (#2089)

macos/FluentUI/DatePicker/DatePickerController.swift

@@ -262,10 +262,17 @@ open class DatePickerController: NSViewController {
 
 		// In this case, we want to use Chinese numerals instead of western
 		// Setting dateStyle to .long before setting the dateFormat will achieve this
-		if calendar.identifier == .chinese && calendar.locale?.languageCode == "zh" {
-			formatter.dateStyle = .long
+		if calendar.identifier == .chinese {
+			let languageCode: String?
+			if #available(macOS 13.0, *) {
+				languageCode = calendar.locale?.language.languageCode?.identifier
+			} else {
+				languageCode = calendar.locale?.languageCode
+			}
+			if languageCode == "zh" {
+				formatter.dateStyle = .long
+			}
 		}
-
 		formatter.dateFormat = "d"
 
 		return formatter