Allow widgets to be reconfigured

When in edit mode, allow widgets to be reconfigured if they allow
reconfiguration.

This also refactors the existing configuration logic to delegate
configuration to a standalone class.

Bug: 318537189
Test: atest WidgetConfigurationControllerTest
Test: atest CommunalWidgetRepositoryImplTest
Test: flashed device and verified configuration works
Flag: ACONFIG com.android.systemui.communal_hub DEVELOPMENT
Change-Id: I32239eff8ac91cb81fc9ef14e41ac64dad03a8f7