Update file system permission dialogs for Read & ReadWrite accesses

This CL updates the permission dialog text:
  - Unify the text of OK/Cancel buttons: now they are just "Allow" and
    "Don't Allow".
  - Update dialog title to use the pattern "Allow this site to ..."
  - Update dialog text for Read access to use the pattern
    "... will be able to view and make its own copies of ...".

- View Directory Permission
  - Before: http://screen/SBibF8KMx4gRb6M
  - After: http://screen/4WnhasY4fFkLjUh
- View Directory Permission (non-persisted)
  - Before: http://screen/5GujhYZYTVGkBMW
  - After: http://screen/C7doiH6XmeMroKr
- View File Permission
  - Before: http://screen/6NLAPBn5m9VLeTv
  - After: http://screen/9ifv8bawjHMN4TM
- View File Permission (non-persisted)
  - Before: http://screen/5h2Ck6eFaP35A7p
  - After: http://screen/8Hb9sKPvSirsjiL

- Read & Write Directory Permission
  - Before: http://screen/Bgi9JP7WUg4WvZL
  - After: http://screen/432Ln2eTmfgFAP6
- Read & Write File Permission
  - Before: http://screen/ATSFjr235Rk4ge2
  - After: http://screen/Bav9nmQbRY8Hc5V

Note that the permission dialog for Write access is NOT changed. The
OK button is still "Save changes". See http://screen/BPSsoZ42d4NQz69.

Bug: 417636712
Change-Id: I2e8a12b2375424e41c3540f76aef0b53c87ba378
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6654434
Reviewed-by: Austin Sullivan <asully@chromium.org>
Commit-Queue: Ming-Ying Chung <mych@chromium.org>
Reviewed-by: Florian Jacky <fjacky@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1481347}