Change std::find_if*() to use base:: functions: c/password_manager/

Goal: Slightly simpler and/or more semantically-accurate code.

Bug: none
Change-Id: I3a9c087075d16c6e25f0323b354534879fab90cb
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3870268


Auto-Submit: Peter Kasting <pkasting@chromium.org>
Reviewed-by: Mohamed Amir Yosef <mamir@chromium.org>
Commit-Queue: Peter Kasting <pkasting@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1042728}