AutoMod RuleTarget __init__: don't be destructive

Since part of RuleTarget.__init__() involves deleting items from the
values dict, this actually changed the dict that was passed to it, which
could have side effects back in the overall Rule creation. Specifically,
this was causing the approve_banned initialization to fail because it
tried to check for the presence of a key that had been destroyed by
this.

r2/r2/lib/automoderator.py

@@ -536,6 +536,8 @@ def __init__(self, target_type, values, parent, approve_banned=True):
 
         if not values:
             values = {}
+        else:
+            values = values.copy()
 
         # determine patterns that will be matched against fields
         self.match_patterns = self.get_match_patterns(values)