fix(ui): fix readonly inputs

There was a props on IAISlider to make the input component readonly - I didn't know this existed and at some point used a component with that prop as a template for other sliders, copying the flag over.

It's not actually used anywhere, so I removed the prop entirely, enabling the number inputs everywhere.

invokeai/frontend/web/src/features/canvas/components/IAICanvasToolbar/IAICanvasToolChooserOptions.tsx

@@ -235,7 +235,6 @@ const IAICanvasToolChooserOptions = () => {
               withInput
               onChange={(newSize) => dispatch(setBrushSize(newSize))}
               sliderNumberInputProps={{ max: 500 }}
-              inputReadOnly={false}
             />
           </Flex>
           <IAIColorPicker