Link to tests.firefox.dev/try.html in the push health summary of the jobs view

[fqueze]

• In the push health summary on the jobs view, the "Failures (N)" text for the Tests category now links to tests.firefox.dev/try.html?rev= when any of the failed test jobs are mochitest or xpcshell.
• The link has a tooltip indicating the number of failed mochitest/xpcshell jobs we'll be looking at.
• The detection is done purely on the frontend by checking the job list for jobs with result === 'testfailed' whose job_type_name contains "xpcshell" or "mochitest".