[Ash] Clean up residual source files in ash/BUILD.gn

Source file references of //chrome/browser/ash/profiles/*.{h,cc} were
left behind in //chrome/browser/ash/BUILD.gn. This CL removes them. This
CL also explicitly adds dependency of //chrome/browser/ash/profiles/*
here and there around the code to satisfy gn check.

Fixed: 335293962
Change-Id: If9dc41930be6d8b7c9d8c3226c0b42a3ade89cfe
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5693880
Reviewed-by: Kyle Horimoto <khorimoto@chromium.org>
Commit-Queue: Di Wu <diwux@google.com>
Cr-Commit-Position: refs/heads/main@{#1326493}