PSA: Disabling automatic flake bisection in Findit

[Joey Scarr‏]

Recently, Findit's flake bisection feature has been incorrectly blaming unrelated culprit CLs for test flakes: https://crbug.com/961339

Due to the high rate of false positives, we have disabled automatic bisection of flaky tests. For now, manual runs can still be triggered from https://analysis.chromium.org/.

- Joey and the TFS team