Fix LoginFragment crash on activity recreation

App can go in background while LoginFragment is visible, where it can be killed by system.
If VncActivity is the recreated, old VncViewModel would be gone and loginType will be null.
Instead of crashing on null loginType, now the LoginFragment is simply dismissed.

app/src/main/java/com/gaurav/avnc/ui/vnc/LoginFragment.kt

@@ -11,6 +11,7 @@ package com.gaurav.avnc.ui.vnc
 import android.app.Dialog
 import android.os.Bundle
 import android.util.ArrayMap
+import android.util.Log
 import android.widget.ArrayAdapter
 import androidx.core.view.isVisible
 import androidx.fragment.app.DialogFragment
@@ -42,6 +43,14 @@ class LoginFragment : DialogFragment() {
     private val loginInfo by lazy { getLoginInfoFromProfile(viewModel.profile) }
 
     override fun onCreateDialog(savedInstanceState: Bundle?): Dialog {
+        if (savedInstanceState != null && viewModel.loginInfoRequest.value == null) {
+            Log.i(javaClass.simpleName, "Activity is being recreated and old ViewModel is gone, removing stale login dialog")
+            showsDialog = false
+            dismiss()
+            return Dialog(requireContext()) // Can't return null
+        }
+
+        check(viewModel.loginInfoRequest.value != null) { "Login fragment invoked without a login type" }
         binding = FragmentCredentialBinding.inflate(layoutInflater, null, false)
 
         binding.loginInfo = loginInfo