To save the user an additional node when randomizing an already existing attribute, the `Attribute Randomize` node should have a selection of different `Mix Modes`:
- replace/create (default)
- add
- multiply.
.
.
.
Same as e.g. `VertexWeightMix` modifier
{F9592667}
Note: The default option should be called 'Replace/Create' to make its functionality clear.