[ios/passwords] Disable account storage switch if blocked by policy

Behavior changes are behind a flag off by default.
Disable the toggle if policies are set in a way such that any of
these hold:
- SyncDisabled == true (disables sync layer overall)
- SyncTypesListDisabled contains passwords
- PasswordManagerEnabled == false

Bug: 1377384
Change-Id: I1b6a45a7aaa0091ed70a46fd3f160209dc48ef81
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4265292


Reviewed-by: Tommy Martino <tmartino@chromium.org>
Commit-Queue: Victor Vianna <victorvianna@google.com>
Quick-Run: Victor Vianna <victorvianna@google.com>
Cr-Commit-Position: refs/heads/main@{#1119480}