SAK-49419 Rubrics: Students can’t view rubric comments within modal

[hornersa]

The z-index of 99999 might seem excessive, but '9999' is not enough. I also use "bs-popover-auto" as the selector because "popover" is used in other contexts as a class name.

[ern]

@hornersa the rubrics modal has a zindex of 10000 and if you remove that then it displays fine.

[ottenhoff]

I left a comment in Jira, but I don't think this fixes issue