[Desktop] remove "Check passwords" UI in settings

[LaurenWags]

Description

When you're on brave://settings/passwords there is an option to "Check passwords". We should remove this UI, it did not show in 1.12.x (C84) but does show with C85 versions of Brave.

Steps to Reproduce

1. Using C85 version (such as 1.13.x)
2. Navigate to brave://settings/passwords

Actual result:

Expected result:

This should not be displayed

Reproduces how often:

easily

Brave version (brave://version info)

Brave	1.13.79 Chromium: 85.0.4183.69 (Official Build) dev (64-bit)
Revision	4554ea1a1171bd8d06951a4b7d9336afe6c59967-refs/branch-heads/4183@{#1426}
OS	macOS Version 10.14.6 (Build 18G3020)

Version/Channel Information:

• Can you reproduce this issue with the current release? 1.12.x no, 1.13.x yes
• Can you reproduce this issue with the beta channel? 1.14.x yes
• Can you reproduce this issue with the nightly channel? 1.15.x yes

Other Additional Information:

• Does the issue resolve itself when disabling Brave Shields?
• Does the issue resolve itself when disabling Brave Rewards?
• Is the issue reproducible on the latest version of Chrome?

Miscellaneous Information:

cc @rebron @bsclifton

[kjozwiak]

Verification PASSED on macOS 10.15.6 x64 using the following build:

Brave | 1.13.82 Chromium: 85.0.4183.83 (Official Build) (64-bit)
-- | --
Revision | 94abc2237ae0c9a4cb5f035431c8adfb94324633-refs/branch-heads/4183@{#1658}
OS | macOS Version 10.15.6 (Build 19G73)

Verified the STR/Cases outlined via both brave/brave-core#6501 (comment) & #11423 (comment).

---

Verification passed on

Brave	1.13.82 Chromium: 85.0.4183.83 (Official Build) (64-bit)
Revision	94abc2237ae0c9a4cb5f035431c8adfb94324633-refs/branch-heads/4183@{#1658}
OS	Ubuntu 18.04 LTS

Verified the STR/Cases outlined via both brave/brave-core#6501 (comment) & #11423 (comment).

---

Verification passed on

Brave | 1.13.82 Chromium: 85.0.4183.83 (Official Build) (64-bit)
-- | --
Revision | 94abc2237ae0c9a4cb5f035431c8adfb94324633-refs/branch-heads/4183@{#1658}
OS | Windows 10 OS Version 1903 (Build 18362.1016)

• Verified the STR/Cases outlined via both Disables password check feature. brave-core#6501 (comment) & [Desktop] remove "Check passwords" UI in settings #11423 (comment).
  
• ensured that Check Password was removed from brave://settings/passwords
• ensure that you can save passwords and they appear under brave://settings/passwords
• ensured that you can login into websites using auto-fill from brave://settings/passwords
• ensured that the Manage button on the modal once you've saved a password works as expected
• ensured that viewing password works as expected
• ensured that clicking on "Details" works as expected
• ensured you can remove the password from brave://settings/passwords via Remove
• upgraded profile with saved passwords and ensured password auto-fill worked as expected
• ensured that all the above cases worked on an existing profile