Checkmk Werk 15958: Custom extensions: Avoid duplicate graphs in the user interface due to `graph_info.append`

ID: 15958 Title: Custom extensions: Avoid duplicate graphs in the user interface due to `graph_info.append` Component: metrics Level: 1 Class: Bug fix Version: 2.2.0p8 This werk only concerns developers of custom Checkmk extensions. There are currently two ways for registering custom graph definitions: C+: graph_info["GRAPH_ID"] = GRAPH_DEFINITION C-: and C+: graph_info.append(GRAPH_DEFINITION) C-: Using the latter might have lead to duplicate graphs in the user interface. As of this werk, this is fixed.