Implemented handling of server side issues using the rfc for problem detasils in the frontend

Moonlight.Frontend/UI/Admin/Views/Sys/Themes/Create.razor

@@ -3,6 +3,7 @@
 @using Microsoft.AspNetCore.Authorization
 @using Moonlight.Shared
 @using LucideBlazor
+@using Moonlight.Frontend.Helpers
 @using Moonlight.Frontend.Services
 @using Moonlight.Shared.Http.Requests.Themes
 @using ShadcnBlazor.Buttons
@@ -118,11 +119,17 @@
     {
         Request.CssContent = await Editor.GetValueAsync();
 
-        await HttpClient.PostAsJsonAsync(
+        var response = await HttpClient.PostAsJsonAsync(
             "/api/admin/themes",
             Request,
             Constants.SerializerOptions
         );
+        
+        if (!response.IsSuccessStatusCode)
+        {
+            await ProblemDetailsHelper.HandleProblemDetailsAsync(response, Request, validationMessageStore);
+            return false;
+        }
 
         await ToastService.SuccessAsync(
             "Theme creation",