network: Show configuration button only for active/connecting connections
In commit c7bd4428 we started to show the configuration button for all rows, which fixes the original issue of not being able to tweak a connection during association but also introduces a regression of not having connection data to show for other connections in the list. This way, the configuration button will fail to create a net_connection_editor interface for rows that aren't associated with an active connection.
Let's only show the configuration button when the NMActiveConnectionState is either NM_ACTIVE_CONNECTION_STATE_ACTIVATING or NM_ACTIVE_CONNECTION_STATE_ACTIVATED.
Fixes #1494 (closed)