[Components - ToggleGroupControl]: Fix visual state when no option is selected

[ntsekouras]

Fixes: #35383

When we pass a value to ToggleGroupControl that doesn't exist in the available options the backdrop should not be visible.

Testing instructions

1. Run storybook
2. Check the With Reset story
3. Observe that the backdrop is not visible when we reset.

The case is being discussed here: https://github.com/WordPress/gutenberg/pull/35395/files#r726460400 and previous mention to the existing code about targetNode is here.

The thing is that this is probably related to Reakit and was related to the fix here: #35409 (that got removed now). The problem is probably that if we have a value in Reakit state that doesn't exist in our options, the currentId is filled with the first available option, which is not what we want. Reakit docs state that if we pass null the currentId will not be set, but with some tests of mine, it still had the first option as value.

--cc @sRahul-00

[ciampo]

Testing the Storybook example, the problem seems to be solved.

I have a question though: with this fix, we're rendering BackdropView with a width of 0. Should we instead look into not rendering that component at all?

[ntsekouras]

I have a question though: with this fix, we're rendering BackdropView with a width of 0. Should we instead look into not rendering that component at all, instead?

I updated the code 😄

[ciampo]

Thank you for Changes LGTM!

I left a small comment, feel free to address it and merge after that.