Move code for browser tests to code-behind.

Marechai/Pages/Admin/BrowserTests.razor.cs

@@ -0,0 +1,13 @@
+using System.Collections.Generic;
+using System.Threading.Tasks;
+using Marechai.Database.Models;
+
+namespace Marechai.Pages.Admin
+{
+    public partial class BrowserTests
+    {
+        List<BrowserTest> _tests;
+
+        protected override async Task OnInitializedAsync() => _tests = await Service.GetAsync();
+    }
+}