Update SearchFlakyTests endpoint documentation #17411

Job	Run time
examples / examples	2m 29s
pre-commit / pre-commit	1m 5s
test / test (3.2, ubuntu-latest)	2m 26s
test / test (2.7, ubuntu-latest)	3m 13s
test / test (jruby-9.4.12.0, ubuntu-latest)	3m 29s
report	7s
	12m 49s

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