android: Match YieldWithInputHint param to 50% experiment

Among the current experimental groups of the YieldWithInputHint study we
chose the one where poll_interval_ms == 1 to extend to 50%. We will
apply this configuration to 50% via a server-side config soon.

Set the parameter to 1 in fieldtrial_testing_config.json as well to make
the testing configuration closer to the experiment.

Bug: 326417367
Change-Id: I6cd99ddf1fe10b0b233c0900b95d165b8f30215f
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6088923
Auto-Submit: Egor Pasko <pasko@chromium.org>
Reviewed-by: Anthony Vallée-Dubois <anthonyvd@chromium.org>
Commit-Queue: Anthony Vallée-Dubois <anthonyvd@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1396772}