remove expired histograms Tabs.IndependentTabCountInSwitcher, Tabs.TabCountInSwitcher

Bug: 1384967
Change-Id: I91fe6a40d7eaebc5b31d843b9f4a099fb1d22014
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4320971


Reviewed-by: Mei Liang <meiliang@chromium.org>
Commit-Queue: Calder Kitagawa <ckitagawa@chromium.org>
Reviewed-by: Calder Kitagawa <ckitagawa@chromium.org>
Auto-Submit: Kale Lettuce <kalettuce@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1115263}