Revert "[PinnedTabs] Integrate pinned tab strip with Tab Switcher"

This reverts commit 05dc8c49e75212a014add375b5337fdb56746831.

Reason for revert: The test in TabSwitcherLayoutPTTest fails consistently on android-12l-landscape-x64-dbg-tests bot.
See build: https://ci.chromium.org/ui/p/chromium/builders/ci/android-12l-landscape-x64-dbg-tests/19257/test-results

Original change's description:
> [PinnedTabs] Integrate pinned tab strip with Tab Switcher
>
> Impl Recording: http://screencast/cast/NTI3NjU2NjIwNzU5NDQ5NnxlMjNhOWZjNS02MA
>
> Change-Id: I89d5d1869ffbaf2babdde1559f5a2708da172af3
> Bug: 436614730
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6872502
> Reviewed-by: Sky Malice <skym@chromium.org>
> Reviewed-by: Christian Dullweber <dullweber@chromium.org>
> Commit-Queue: Madhav Pruthi <madhavpruthi@google.com>
> Cr-Commit-Position: refs/heads/main@{#1513008}

Bug: 436614730, 443971313
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Change-Id: Iace667a55eb6a2c7954d23037fd5b0cd5aaf56f8
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6930281
Commit-Queue: Madhav Pruthi <madhavpruthi@google.com>
Reviewed-by: Madhav Pruthi <madhavpruthi@google.com>
Commit-Queue: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Auto-Submit: Anna Tsvirchkova <atsvirchkova@google.com>
Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Owners-Override: Anna Tsvirchkova <atsvirchkova@google.com>
Cr-Commit-Position: refs/heads/main@{#1513105}