[FIX] Knox tab: Add lines

RT-2412
Add header bottom-border and left border, to look like other Fund tabs.
[FIX] Knox tab: Fix verify link underline bleeding

RT-2412
Fix problem with the underline "bleeding" of the "Verify identity" link
into the space left to it.
[TASK] Knox tab: Update messages

RT-2412
Update error messages for identity verification, add SnapSwap email
address, fix typos.
Merge pull request #1633 from jublonet/issue/2412-knox-tab-styling

[FIX] RT-2412 Knox tab: Fix styling, strings
[FIX] Popup: Clicking on buttons should close the popup