[fenix] For https://github.com/mozilla-mobile/fenix/issues/19132 - Fix navigation on disconnect started from tabsTray

- Added checks to popBackStack from the Disconnect Logged-in User Dialog, either back to settings, browserFragment or homeFragment.

app/src/main/java/org/mozilla/fenix/settings/account/SignOutFragment.kt

@@ -66,9 +66,10 @@ class SignOutFragment : AppCompatDialogFragment() {
                 accountManager.logout()
             }.invokeOnCompletion {
                 runIfFragmentIsAttached {
-                    if (!findNavController().popBackStack(R.id.settingsFragment, false)) {
+                    if (this.isVisible) {
                         dismiss()
                     }
+                    findNavController().popBackStack()
                 }
             }
         }