Improve the open in new tab behaviour of links on the outcomes reports

Originally spotted in MDL-40230 (introduction of the new outcomes system).

On the Activity and Performance report you can click on "Associated content" and on the Coverage report you can click on the number in the activities column to pop up a dialogue that lists relevant activities.

1) There's no way to click through to those activities.

2) If you right click the link that opens the dialogue and select "open new tab" you just get the same page.