Revert "Refactor culture selection logic with formatCulture"

This reverts commit debfcde.

Author: Krishanthaudayakumara

src/Sitecore.AspNetCore.SDK.RenderingEngine/TagHelpers/Fields/DateTagHelper.cs

@@ -67,10 +67,8 @@ public override void Process(TagHelperContext context, TagHelperOutput output)
 
         CultureInfo culture = !string.IsNullOrWhiteSpace(Culture) ? CultureInfo.CreateSpecificCulture(Culture) : CultureInfo.CurrentCulture;
 
-        CultureInfo formatCulture = !string.IsNullOrWhiteSpace(Culture) ? culture : CultureInfo.InvariantCulture;
-
         string formattedDate = !string.IsNullOrWhiteSpace(DateFormat)
-            ? field.Value.ToString(DateFormat, formatCulture)
+            ? field.Value.ToString(DateFormat, !string.IsNullOrWhiteSpace(Culture) ? culture : CultureInfo.InvariantCulture)
             : field.Value.ToString(culture);
 
         HtmlString html = outputEditableMarkup ? new HtmlString(field.EditableMarkup) : new HtmlString(formattedDate);