[FilesBulkPinning] Update more OS settings strings

 1. Introduces a sublabel to the Google Drive row when the bulk pinning
    feature is enabled and drive is enabled.
 2. Updates the disconnect text to now read as "Remove Drive Access" as
    per UX strings guidelines.

Bug: b:289736284
Fixed: b:289858567, b:288039716
Test: browser_tests --gtest_filter=*OSSettingsOsFilesPage*
Change-Id: Id74cc28f1fcf0b4135c7eae7be51db559b385450
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4671966


Reviewed-by: François Degros <fdegros@chromium.org>
Reviewed-by: Wes Okuhara <wesokuhara@google.com>
Commit-Queue: Ben Reich <benreich@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1168400}