[@mantine/hooks] use-focus-trap: Fix aria-hidden

[Keilo75]

This PR resolves #2726.

Turns out that restoreAria.current(); was simply not called on unmount; this has now been changed.
Furthermore, I fixed an additional issue where aria-hidden attributes would only be applied on the first render, but would not update after that. This was caused by

mantine/src/mantine-hooks/src/use-focus-trap/use-focus-trap.ts

Line 16 in f7da145

if (node === ref.current || node === null) {

After the first render, ref.current would already hold the node and aria attributes would not be reapplied again.

Finally, I added a test to FocusTrap.test.tsx which makes sure aria-hidden is added and removed. I'll be the first to admit it is kinda ugly but I could not find a better version. Also tested it manually with storybook - components like Modal or Drawer now remove the attribute correctly.

[rtivital]

Thanks!