Fix bugs encountered when trying to edit multiple DecayTreeTuples

the bug was primarily in the structure of SelectVariables.state, where row.dtt was inconsistently a DTTConfig object (which has a .config key) or itself the .config from an older DTTConfig

also caught two other bugs:

• TupleTool metadata was not being passed on DTTConfig creation
• could not download info.yaml because it still expected row.paths to be a list of choice-objects intended for react-select