[cr93 followup] Removed disablement of kEnablePasswordsAccountStorage.

[mkarolin]

Fixes brave/brave-browser#17595

This feature flag no longer works as all the code it wasn't guarding has
been removed and password account storage is the only option now.

This also means that we will regress on
brave/brave-browser#16926 again, and needs a different fix added here in a separate commit.

Chromium issue:

https://bugs.chromium.org/p/chromium/issues/detail?id=1108738

https://chromium.googlesource.com/chromium/src.git/+/90ac58cb2c56df119ca3d5631cbbc3feabb8a82b

commit 90ac58cb2c56df119ca3d5631cbbc3feabb8a82b
Author: Marc Treib treib@chromium.org
Date: Fri Jul 9 10:43:20 2021 +0000

B4P cleanup, part 2: Delete old Save/Update bubble

PasswordSaveUpdateView has been replaced by
PasswordSaveUpdateWithAccountStoreView, similar for the corresponding
controller. This CL deletes the old, non-AccountStore versions.

This is a no-op on Win/Mac/Linux/ChromeOS (which already always used
the new versions) and on Android/iOS (which don't use this UI at all).
(Note that ChromeOS doesn't actually use/support the account-scoped
storage, since the signed-in non-syncing state doesn't exist. But the
new UI code is a strict superset of the old, so using it on ChromeOS as
well is just simpler and more consistent - and this was already the
case.)

This CL also ports some recent unit test improvements (see
crrev.com/c/3006215) from the old to the new controller.

Bug: 1108738

Submitter Checklist:

• I confirm that no security/privacy review is needed, or that I have requested one
• There is a ticket for my issue
• Used Github auto-closing keywords in the PR description above
• Wrote a good PR/commit description
• Added appropriate labels (QA/Yes or QA/No; release-notes/include or release-notes/exclude; OS/...) to the associated issue
• Checked the PR locally: npm run test -- brave_browser_tests, npm run test -- brave_unit_tests, npm run lint, npm run gn_check, npm run tslint
• Ran git rebase master (if needed)

Reviewer Checklist:

• A security review is not needed, or a link to one is included in the PR description
• New files have MPL-2.0 license header
• Adequate test coverage exists to prevent regressions
• Major classes, functions and non-trivial code blocks are well-commented
• Changes in component dependencies are properly reflected in gn
• Code follows the style guide
• Test plan is specified in PR before merging

After-merge Checklist:

• The associated issue milestone is set to the smallest version that the
  changes has landed on
• All relevant documentation has been updated, for instance:
  • https://github.com/brave/brave-browser/wiki/Deviations-from-Chromium-(features-we-disable-or-remove)
  • https://github.com/brave/brave-browser/wiki/Proxy-redirected-URLs
  • https://github.com/brave/brave-browser/wiki/Fingerprinting-Protections
  • https://github.com/brave/brave-browser/wiki/Brave%E2%80%99s-Use-of-Referral-Codes
  • https://github.com/brave/brave-browser/wiki/Custom-Headers
  • https://github.com/brave/brave-browser/wiki/Web-Compatibility-Exceptions-in-Brave
  • https://github.com/brave/brave-browser/wiki/QA-Guide
  • https://github.com/brave/brave-browser/wiki/P3A

Test Plan:

[fmarier]

Note: this does both the login page and the change password page. That looks okay to me.