chase: Handle both CSV schemata

Apparently, Chase has switched back to the CSV schema without the Card
column at the beginning.  Just in case they decide to flip-flop on that
field forever, we better try to handle both cases.

xactfetch.py

@@ -638,6 +638,16 @@ class Chase:
     def firefly_import(self, csv: Path, account: int, token: str) -> None:
         config = copy.deepcopy(self.IMPORT_CONFIG)
         config['default_account'] = account
+        with csv.open('r', encoding='utf-8') as f:
+            headers = f.readline()
+        if headers.startswith('Card'):
+            log.debug('Detected CSV schema with Card column')
+        elif headers.count(',') == 6:
+            log.debug('Detected CSV schema without Card column')
+            config['roles'].pop(0)
+            config['do_mapping'].pop(0)
+        else:
+            raise ValueError(f'Unexpected CSV schema: {headers}')
         firefly_import(csv, config, token)