Remove the trailing "," in signaturesDB (#766)

That corresponding statement in worst case is `if (False or False or False,)` simplifies to `if (False,):`  which simplifies to `True` , so the code below is unreachable

mythril/support/signatures.py

@@ -129,7 +129,7 @@ def get(self, byte_sig: str, online_timeout: int = 2) -> List[str]:
         if (
             not self.enable_online_lookup
             or byte_sig in self.online_lookup_miss
-            or time.time() < self.online_lookup_timeout,
+            or time.time() < self.online_lookup_timeout
         ):
             return []