Save empty journal on install instead of just creating a zero-length file (#1690)

* Add failing test for issue #1493
* Write journal upon creation instead of just creating 0-length file
* Fix test to accommodate current password mocking form

jrnl/journals/Journal.py

@@ -123,6 +123,7 @@ class Journal:
                     },
                 )
             )
+            self.write()
 
         text = self._load(filename)
         text = self._decrypt(text)