Remove Dataflow Data source when it is no longer used in the dataflow

[mattis_kristoff]

 Currently there is no way of removing data sources in the settings menu of a data flow causing issues when refreshing the data etc. The current workaround is to download the JSON file and re-upload the JSON-file again. However, this will duplicate the data flow, but will not include any obsolete data source used in the data flow.

We would like to propose to add functionality to be able to remove data source in the settings menu in a workspace.

[Isherwood_James]

Please update this issue with an official response or documentation as it is incredibly frustrating. Thanks.