Fix docs for control inputs with initial checked state

[sukhrajghuman]

Since this is an uncontrolled component, passing the checked attribute in <AUradio> and <AUcheckbox> is overriding the checked attribute in the DOM. This means the checkbox/radio box will remain checked. If we use defaultChecked, it will be checked initially and allow for subsequent updates to be uncontrolled.

fixes #544

I'm also going to put #548 on hold for now. I believe it's fairly low priority.

[azerella]

I don't see where you've changed the prop definitions for the AUradio component ?

[sukhrajghuman]

no need to change it for the actual component itself. It's just a fix in the example. then will update the example in designsystem.gov.au.

I updated my comment in the PR to make it more clear.
See below as well
https://codesandbox.io/s/3v65nqxkvp

[azerella]

@sukhrajghuman Now I'm more confused lol, the codepen example sets defaultChecked={true} and defaultChecked="some text". Is this correct way to use the prop?

[sukhrajghuman]

It sets defaultChecked={true} and *defaultValue*="some text". try editing the text or unclicking the text-input and checkbox examples

[azerella]

@sukhrajghuman Ahh, gotcha - LGTM

[alex-page]

We need to clean these PR's up they have a lot of unrelated file changes 👍

[azerella]

@alex-page Fixed with a rebase