Fix duplicate list processing in password upgrade check

Add deduplication by internal_name() to prevent the same list from being
processed multiple times when checking for old password formats. This fixes
an issue where the same list could appear multiple times in the output with
different email addresses.

Author: jared mauch

bin/update

@@ -683,6 +683,7 @@ def check_and_notify_password_upgrades(dry_run=False):
 
     print('Checking for lists with old password formats...')
     lists_needing_upgrade = []
+    seen_lists = {}  # Track by internal name to avoid duplicates
 
     # Check all lists for old password formats
     listnames = Utils.list_names()
@@ -694,6 +695,13 @@ def check_and_notify_password_upgrades(dry_run=False):
             'listname': listname, 'e': e})
             continue
 
+        # Use internal_name() as key to avoid processing the same list twice
+        internal_name = mlist.internal_name()
+        if internal_name in seen_lists:
+            # Already processed this list, skip
+            continue
+        seen_lists[internal_name] = True
+        
         needs_upgrade = False
         # Check list admin password
         if mlist.password and is_old_password_format(mlist.password):