Resolve "Incorrect SFGs do not raise"

Closes #165 (closed) . Modifies 'replace_operation' to handle the case 'sfg.replace_operation(Sink(), "out0")' without raising error. Adds test for "Keep graph_id if possible"

b_asic/signal_flow_graph.py

@@ -305,7 +305,7 @@ class SFG(AbstractOperation):
 
         if len(output_sources) != (output_operation_count + output_signal_count):
             raise ValueError(
-                "At least one output signal is not connected!, Tips: Check for output ports that are connected to the same signal"
+                "At least one output operation is not connected!, Tips: Check for output ports that are connected to the same signal"
             )
 
     def __str__(self) -> str: