Fix encrypt / decrypt menu items display

src/main/java/com/kdanmobile/reader/ReaderActivity.kt

@@ -311,7 +311,7 @@ abstract class ReaderActivity :
         }
         menu?.apply {
             val isPdf = isPdf()
-            when (password.isEmpty()) {
+            when (!isPasswordProtected) {
                 true -> {
                     findItem(R.id.item_reader_more_encrypt)?.isVisible = isPdf
                     findItem(R.id.item_reader_more_decrypt)?.isVisible = false