Remove expired MediaDeviceNotification.UdevRequestSuccess histogram

This decade old histogram should have been removed a long time ago, but
it was checked into a different repo and thus avoided expiration audits
for a long time. After it was moved into the main Chromium repo, now it
finally expired.

The success rate is over 99.9% for this Linux-only metric. Since Storage
Monitor and Media Galleries are not in active development, there is no
planned action to get the success rate higher. Thus stop recording this
metric and remove the associated code.

Bug: 324896799
Change-Id: Id57d0bc020b3c1ea8aef8b2b4f6df58aa950074e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5293334
Commit-Queue: Lei Zhang <thestig@chromium.org>
Reviewed-by: Tommy Li <tommycli@chromium.org>
Reviewed-by: Evan Liu <evliu@google.com>
Cr-Commit-Position: refs/heads/main@{#1260700}