a11y: Fix keyboard navigation and focus display for about page

[nwmac]

a11y Issue: 215

The about page (see below) does not show keyboard focus and does not response to keyboard navigation.

The download links are not in the tab order.

Generally need to check the tab order through the page.

Focus display for the primary 'Diagnostics' button needs to be checked.

[yonasberhe23]

Needs manual validation at this time as we dont have existing accessiblity tests. Follow-up ticket to create automated tests coverage rancher/qa-tasks#1639

[IsaSih]

Navigation using tab and return work as expected in
Rancher | v2.11-1e40bc40c55a020fc67dc3c3dde47b41dc94caf1-head
Dashboard | master 574248d
Rancher CLI | v2.11.0-rc.1
Helm | dev
Machine | v0.15.0-rancher125

However, the space bar does not perform click actions in elements inside the table.
Just want to confirm @nwmac if this is working as expected? I reopened the issue because I believe that space should also perform the same actions as the return/enter keyboard shortcut

[aalves08]

The decision made is that "links" that appear as buttons are to have the space key as trigger as simple links, anchors, non-button links should not have the space key as trigger, as per #12959 (comment) + #12959 (comment)

[IsaSih]

Then, the accessibility behavior is working as expected. Closing the issue