fix(ui): show ALPN values that are not in the preset list (#10604)

The ALPN combo box only lists a few fixed combinations. A node imported
with another value, for example "h2,http/1.1,h3", keeps it, but the
edit dialog shows an empty field and there is no way to enter such a
value by hand. Make the combo box editable like the fingerprint one, so
any stored value is shown and can be changed.

The Desktop window had the same problem for the fingerprint combo boxes
(for example "randomizednoalpn"); make them editable and bind their
text, as the WPF window already does.

v2rayN/v2rayN.Desktop/Views/AddServerWindow.axaml

@@ -1415,7 +1415,8 @@
                         Grid.Row="2"
                         Grid.Column="1"
                         Width="200"
-                        Margin="{StaticResource Margin4}" />
+                        Margin="{StaticResource Margin4}"
+                        IsEditable="True" />
 
                     <TextBlock
                         Grid.Row="3"
@@ -1428,7 +1429,8 @@
                         Grid.Row="3"
                         Grid.Column="1"
                         Width="200"
-                        Margin="{StaticResource Margin4}" />
+                        Margin="{StaticResource Margin4}"
+                        IsEditable="True" />
 
                     <TextBlock
                         Grid.Row="4"
@@ -1581,7 +1583,8 @@
                         Grid.Row="1"
                         Grid.Column="1"
                         Width="200"
-                        Margin="{StaticResource Margin4}" />
+                        Margin="{StaticResource Margin4}"
+                        IsEditable="True" />
 
                     <TextBlock
                         Grid.Row="2"

v2rayN/v2rayN.Desktop/Views/AddServerWindow.axaml.cs

@@ -195,8 +195,8 @@ public partial class AddServerWindow : WindowBase<AddServerViewModel>
             this.Bind(ViewModel, vm => vm.SelectedSource.StreamSecurity, v => v.cmbStreamSecurity.SelectedValue).DisposeWith(disposables);
             this.Bind(ViewModel, vm => vm.SelectedSource.Sni, v => v.txtSNI.Text).DisposeWith(disposables);
             this.Bind(ViewModel, vm => vm.AllowInsecure, v => v.togAllowInsecure.IsChecked).DisposeWith(disposables);
-            this.Bind(ViewModel, vm => vm.SelectedSource.Fingerprint, v => v.cmbFingerprint.SelectedValue).DisposeWith(disposables);
+            this.Bind(ViewModel, vm => vm.SelectedSource.Fingerprint, v => v.cmbFingerprint.Text).DisposeWith(disposables);
-            this.Bind(ViewModel, vm => vm.SelectedSource.Alpn, v => v.cmbAlpn.SelectedValue).DisposeWith(disposables);
+            this.Bind(ViewModel, vm => vm.SelectedSource.Alpn, v => v.cmbAlpn.Text).DisposeWith(disposables);
             this.Bind(ViewModel, vm => vm.CertSha, v => v.txtCertSha256Pinning.Text).DisposeWith(disposables);
             this.Bind(ViewModel, vm => vm.CertTip, v => v.labCertPinning.Text).DisposeWith(disposables);
             this.Bind(ViewModel, vm => vm.Cert, v => v.txtCert.Text).DisposeWith(disposables);
@@ -205,7 +205,7 @@ public partial class AddServerWindow : WindowBase<AddServerViewModel>
 
             //reality
             this.Bind(ViewModel, vm => vm.SelectedSource.Sni, v => v.txtSNI2.Text).DisposeWith(disposables);
-            this.Bind(ViewModel, vm => vm.SelectedSource.Fingerprint, v => v.cmbFingerprint2.SelectedValue).DisposeWith(disposables);
+            this.Bind(ViewModel, vm => vm.SelectedSource.Fingerprint, v => v.cmbFingerprint2.Text).DisposeWith(disposables);
             this.Bind(ViewModel, vm => vm.SelectedSource.PublicKey, v => v.txtPublicKey.Text).DisposeWith(disposables);
             this.Bind(ViewModel, vm => vm.SelectedSource.ShortId, v => v.txtShortId.Text).DisposeWith(disposables);
             this.Bind(ViewModel, vm => vm.SelectedSource.SpiderX, v => v.txtSpiderX.Text).DisposeWith(disposables);

v2rayN/v2rayN/Views/AddServerWindow.xaml

@@ -1657,6 +1657,7 @@
                         Grid.Column="1"
                         Width="200"
                         Margin="{StaticResource Margin4}"
+                        IsEditable="True"
                         Style="{StaticResource DefComboBox}" />
 
                     <TextBlock