Make Radio Button groups more composable

[lucas-homer]

In AQE2, we have requirements for a radio button group where one option, when selected, should enable a supplemental dropdown input. See screenshot.. In the screenshot, you can see we were forced to put the optional dropdown below the radio button group, but we want to show it 'indented' so we can capture the fact that it's an optional "sub-field" only applicable when a particular radio button is the selected value.

At present, the SQFormRadioButtonGroup component only accepts children in the shape of an array of objects including label, value, and a few other properties. This is fine for simple/happy path cases, but in some cases we can have more customized requirements like the requirements in the AQE2 Extra Help radio button group. It would be handy to be able to do something like this, where children is an array of JSX Elements instead of an array of POJOs:

<SQFormRadioButtonGroup groupLabel="Extra Help">
  <SQFormRadioButton name="extraHelpLevel" label="I am not eligible" value="1" />
  <SQFormRadioButton name="extraHelpLevel" label="I receive Full Extra Help" value="2" />
  <SQFormRadioButton name="extraHelpLevel" label="I receive Partial Extra Help" value="3" />
    {values.extraHelpLevel === "3" && (
      <SomeCustomDropdown /> // uses `useSQFormContext` to dynamically render/enable
    )}
  <SQFormRadioButton name="extraHelpLevel" label="I do not receive any Extra Help" value="4" />
</SQFormRadioButtonGroup>

[lucas-homer]

dropping this here for reference -- https://selectquote.atlassian.net/browse/AQE2-1084