Fix supported layout for the QR Code

The additional code entry in the layout must be optional, not required.
Otherwise this invalidates QR Codes that do not have any code associated
with them.

pam/internal/adapter/authmodeselection.go

@@ -102,7 +102,7 @@ func (m *authModeSelectionModel) Init() tea.Cmd {
 				{
 					Type:    "qrcode",
 					Content: &required,
-					Code:    &required,
+					Code:    &optional,
 					Wait:    &requiredWithBooleans,
 					Label:   &optional,
 					Button:  &optional,