dillon1000/react

Add blur() and focusLast() to fragment instances (#32654)

`focus()` was added in https://github.com/facebook/react/pull/32465.
Here we add `focusLast()` and `blur()`. I also extended `focus` to take
options.

`focus` will focus the first focusable element. `focusLast` will focus
the last focusable element. We could consider a `focusFirst` naming or
even the `focusWithin` used by test selector APIs as well.

`blur` will only have an effect if the current `document.activeElement`
is one of the fragment children.