Button Group widget config "Value", "Label" inconsistency

### Current Behavior

Config options for a radio group widget have Value to the left, Label to the right.
Config options for a button group widget have Label to the left, Value to the right.
Config options for a dropdown widget have Value to the left, Label to the right.

### Expected Behavior

The button group widget should comply with the other two widgets.

ie Value on the left, then Label [Icon, which only occurs on this widget, on the right].

### Steps To Reproduce


### Environment

- Dashboard version: 1.15
- Node-RED version: 4.0.2
- Node.js version:
- npm version:
- Platform/OS:
- Browser:

### Have you provided an initial effort estimate for this issue?

I have provided an initial effort estimate