Bug: version switcher of compositions

[ndelangen]

Closes #21505

What I did

• I ensured the version switcher closes when you click outside
• I ensure the version switcher closes when you click another version
• I ensured the ref enters a loading state when a new version is being requested

How to test

• add a ref

  refs: {
    'design-system': {
      title: 'Design System',
      url: 'https://master--5ccbc373887ca40020446347.chromatic.com',
    },
  },

... to code/ui/.storybook/main.ts

• start the ui storybook
• open the browser
• go to the ref
• change version

Expect that the version switcher closes
Expect that the ref enters the loading state
Expect that after some time, the ref shows again, and the same story is still selected. (assuming the same sotry existed in the other version)

[tmeasday]

LGTM @ndelangen! I noticed that the ref still starts off in the error state before it loads the first time. I'm not sure if that was something this PR was targetting as well, but I thought I'd mention it.

[ndelangen]

I noticed that the ref still starts off in the error state before it loads the first time. I'm not sure if that was something this PR was targeting as well, but I thought I'd mention it.

Will try to fix that in another PR.