inara: Wrap the <var> := <dict get> in () so <var> isn't a bool

Because, yes, 'is not' binds more tightly than ':='.

plugins/inara.py

@@ -673,7 +673,7 @@ def journal_entry(  # noqa: C901, CCR001
                         'starsystemBodyCoords': [entry['Latitude'], entry['Longitude']]
                     }
                     # Not present on, e.g. Ancient Ruins
-                    if market_id := entry.get('MarketID') is not None:
+                    if (market_id := entry.get('MarketID')) is not None:
                         to_send['marketID'] = market_id
 
                     new_add_event('setCommanderTravelLocation', entry['timestamp'], to_send)