Order import: Ignore completely empty lines

src/pretix/base/services/orderimport.py

@@ -95,6 +95,8 @@ def import_orders(event: Event, fileid: str, settings: dict, locale: str, user)
 
         # Run validation
         for i, record in enumerate(parsed):
+            if not any(record.values()):
+                continue
             values = {}
             for c in cols:
                 val = c.resolve(settings, record)

src/tests/base/test_orderimport.py

@@ -85,6 +85,7 @@ def inputfile_factory():
             'J': '2021-06-28 11:00:00',
             'K': '+4962213217750',
         },
+        {},
         {
             'A': 'Anke',
             'B': 'Müller',