[Translate metrics cleanup] Remove Assistant.VoiceSearch.* histograms

OBSOLETE_HISTOGRAM[Assistant.VoiceSearch.AgsaVersion{Timing}]=No longer used, deprecated in M116
OBSOLETE_HISTOGRAM[Assistant.VoiceSearch.ConsentOutcome]=No longer used, deprecated in M116
OBSOLETE_HISTOGRAM[Assistant.VoiceSearch.UserEligibility.FailureReason{Timing}]=No longer used, deprecated in M116
OBSOLETE_HISTOGRAM[Assistant.VoiceSearch.UserEligibility{Timing}]=No longer used, deprecated in M116

Bug: 1447805
Change-Id: I096ea28075534138f202545bbb2d796636de1f64
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4638167


Commit-Queue: Xiaohui Chen <xiaohuic@chromium.org>
Reviewed-by: Xiaohui Chen <xiaohuic@chromium.org>
Auto-Submit: Anthony Cui <cuianthony@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1161973}