Add Polish to supported UI cultures

ErsatzTV/Startup.cs

@@ -605,7 +605,7 @@ public class Startup
         {
             CultureInfo[] cinfo = CultureInfo.GetCultures(CultureTypes.AllCultures & ~CultureTypes.NeutralCultures);
             string[] supportedCultures = cinfo.Select(t => t.Name).Distinct().ToArray();
-            string[] supportedUiCultures = ["en-us", "pt-br"];
+            string[] supportedUiCultures = ["en-us", "pl", "pt-br"];
             options.AddSupportedCultures(supportedCultures)
                 .AddSupportedUICultures(supportedUiCultures)
                 .SetDefaultCulture("en-us");