Downloading MFA backup codes shouldn't open new tab

[noah-schechter]

[Not a deployment blocker]

Current On Safari, downloading MFA backup codes opens a new tab with a URL of about:blank. On Chrome, the same occurs, but the tab automatically closes a moment later.

Proposed Ideally, MFA backup code download behavior would mirror that of CSV export—Atlos doesn't open a new tab, it just downloads the codes to a .txt file.

[milesmcc]

Actually had to make CSV export behave this way to fix breaking the incidents page. Will explore longer term if there's a way to make the page close automatically.