Add field_trial_testing_config entry to begin removing SBER on Bling.

This entry differs from 'ExtendedReportingRemovePrefDependency' since
we don't need to send HPRT pings on iOS. These are used on other
platforms to supplement the CSBR reports that are lost when disabling
SBER. Bling didn't send CSBR reports so we don't have this concern.

Bug: 444243524
Change-Id: I79c1ff152b6039ff27227b66d3546ee8a02a9911
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6956927
Commit-Queue: Kirubel Aklilu <kaklilu@chromium.org>
Reviewed-by: Sergio Collazos <sczs@chromium.org>
Reviewed-by: Zack Han <zackhan@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1518235}