No way to close Link UI unless in "edit" mode

[getdave]

Currently the "Cancel" button is only displayed when you are in editing mode. This will close the UI. However if you are simply previewing the link (and not editing) there is no means of closing the UI other than clicking away.

I believe it is this which causes problems for users of assistive tech. Seems related to #47327.

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When editing a link, there's no 'cancel' option unless you're currently editing; the preview state of a link isn't cancellable. If a keyboard user tabs into the link control panel, they aren't offered a clear way to exit.

Originally posted by @joedolson in #47310 (comment)

[richtabor]

they aren't offered a clear way to exit.

Is esc not clear/standard?

[joedolson]

esc is standard, but requires prior knowledge to be aware that it's available. Particularly for users with cognitive impairments, having a clearly labeled control to exit is important. Giving users a perceivable exit path supports users who don't know the invisible exits (clicking outside of the UI or Esc).

[getdave]

@richtabor I think we should review the designs in #50891 with the a11y team and see if there's anything that has been missed.

I would recommend that we do the ground work to come up with a list of potential a11y concerns and ask them for their feedback on these. If there is any additional feedback we can also look into that.

Happy to help with this.

[richtabor]

@richtabor I think we should review the designs in #50891 with the a11y team and see if there's anything that has been missed.

Just closing the loop that we've conducted the review per #50950