Raise an exception when initializing callbacks with circular dependencies

[chriddyp]

@app.callback(Output('my-graph', 'figure'), [Input('my-graph', 'figure')])

Our users do this pretty often. For example, see here: https://community.plot.ly/t/object-as-input-output-error-loading-dependencies/12492

[chuyachia]

Hi, I would like to help on this one. Does this look like what you have in mind?
https://github.com/chuyachia/dash/blob/callback-circular-deps-exception/dash/dash.py#L568-L578

[zouhairm]

This is kind of related to https://github.com/plotly/dash-renderer/issues/76
If an exception is going to be raised by default, there should be a way to suppress it in the config to allow for circular dependencies