use test_file_finder mapping to spot flaky tests

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Release notes

Problem to solve

As a developer reviewing an MR, I want to quickly identify which failed tests could be flaky, so that I can focus on fixes to code I really broke.

This could be a nice iteration on #241759 (closed)

Proposal

If a user has implemented mapping via test_file_finder we should be able to figure out a test maps to a file that changed or not and then message that in the Test Summary Widget like this, but you know with better words.

1. Hey we noticed this test failed and you changed code related to it, so go look at your code.
2. Hey we noticed this test failed but you didn't change code related to it . . but it hasn't failed before, that's weird maybe it's flaky?!
3. Hey we noticed this test failed and it's failed in a few of the last runs but not all of them, it could be flaky.