[CSC] Remove CSC from Chromium

I verified everything still works on Chrome and the following no longer
on Chromium:
1) CSC 3 dot menu entrypoint no longer appears
2) Region search entrypoint doesn't appear (existing behavior)
3) Image search context menu does not open CSC
4) Text search context menu does not appear
5) CSC missing from side panel drop down menu

AFAIK, these are all the entrypoints into CSC.

Bug: b:306702852
Change-Id: If8d63b750164079d18ab89d662fd0dd35a1709ba
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4966950
Reviewed-by: Michael Crouse <mcrouse@chromium.org>
Commit-Queue: Duncan Mercer <mercerd@google.com>
Cr-Commit-Position: refs/heads/main@{#1215241}