Adopt base::NoDestructor for KeyedService factories

It replaces base::Singleton, following the latest recommendation
in base/ and browser_context_keyed_service_factory.h.

For factories with no logic in the destructor, it makes no difference.

LSC doc:
https://docs.google.com/document/d/1x1LqRQyfBOmpMkNQBYs7QBPSxLtuiImvmgcJYI_kaS4/edit?usp=sharing

Change-Id: Ifbc18cb2b66a3275ede5b45ccc959f1ea44a140a
Bug: 925323
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4561735
Commit-Queue: Mikel Astiz <mastiz@chromium.org>
Reviewed-by: Marc Treib <treib@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1153184}