Rename CommunalWidgetRepositoryImpl

This change renames the CommunalWidgetRepositoryImpl to
CommunalWidgetRepositoryLocalImpl, indicating that this implementation
manages data locally, in contrast to the upcoming
CommunalWidgetRepositoryRemoteImpl, which gets data through a remote
service.

Test: NONE simple renaming
Bug: 357621815
Flag: EXEMPT simple renaming

Change-Id: I27887eb9bcedae884b6d4e2cb44a14a9c846c8e3