monitor/NavRoute: Load NavRoute after catching_up ends.

This is to allow restart of EDMarketConnector whilst the game is running
to have `state['NavRoute']` hold data when the synthetic `StartUp` event
is passed to plugins.

NB: Probably need to note this in PLUGINS.md

monitor.py

@@ -397,6 +397,12 @@ class EDLogs(FileSystemEventHandler):  # type: ignore # See below
                 except Exception as ex:
                     logger.debug(f'Invalid journal entry:\n{line!r}\n', exc_info=ex)
 
+            # One-shot attempt to read in latest NavRoute, if present
+            navroute_data = self._parse_navroute_file()
+            if navroute_data is not None:
+                # If it's NavRouteClear contents, just keep those anyway.
+                self.state['NavRoute'] = navroute_data
+
             self.catching_up = False
             log_pos = loghandle.tell()