[ios] Rename last method/prefs of ProfileAttributeStorageIOS

Ensure that ProfileAttributesStorageIOS only refer to Profile instead
of BrowserState in its API and implementation by renaming the last
methods and preferences that were still using the old name.

Fixed: 359522668
Change-Id: I11d5d9a0342ce31058d3f6f6878ce7cd96caadd2
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5809158
Commit-Queue: Federica Germinario <fedegermi@google.com>
Auto-Submit: Sylvain Defresne <sdefresne@chromium.org>
Reviewed-by: Federica Germinario <fedegermi@google.com>
Code-Coverage: findit-for-me@appspot.gserviceaccount.com <findit-for-me@appspot.gserviceaccount.com>
Cr-Commit-Position: refs/heads/main@{#1346608}