a11y view is blank after running `focus comment on line`

[amunger]

adding some detail to the repro steps

1. add a comment to a line in a PR
2. checkout the PR locally and run focus comment current line while on that line - comment is focused with a border
3. press alt + f2 to open a11y view

🐛 view content is empty

Originally posted by @amunger in #226087 (comment)

[meganrogge]

You're focusing the thread widget, not a comment within it.

Maybe we should automatically focus the first comment in the thread for this case @alexr00 ?

[alexr00]

We can do that! Do you think this should be a canddiate?

[alexr00]

Wait, I thought we just added an accessible view for comment threads.

[alexr00]

Ah no, that was for individual comments. Yes, we can do this.