[SG-467] Fix environment url validations (#1999)

* [SG-467] Fixed url validation so it works with or without http or https

* [SG-467] Validation has been refactored for simplicity.

src/App/Pages/Accounts/EnvironmentPageViewModel.cs

@@ -70,7 +70,7 @@ namespace Bit.App.Pages
         {
             bool IsUrlValid(string url)
             {
-                return string.IsNullOrEmpty(url) || Uri.IsWellFormedUriString(url, UriKind.Absolute);
+                return string.IsNullOrEmpty(url) || Uri.IsWellFormedUriString(url, UriKind.RelativeOrAbsolute);
             }
 
             return IsUrlValid(BaseUrl)