2.14.0 Block colorpicker transparent swatch doesn't trigger onChange
```
<BlockPicker                                                                                    
  color="#ffffff"                                                                               
  colors={['#FF0000','transparent']}                              
  onChangeComplete={ handleColorChange }                                                        
  onChange={ handleColorChange }                                                                
/>  
```
Will never trigger handleColorChange on click of the 'transparent' swatch.
Works correct in 2.13

