Always send configuration change if only desk uiMode changed

Devices with config_skipActivityRelaunchWhenDocking do not relaunch
activities when docking for a better user experience, but should
still send onConfigurationChanged to activities. While some paths in
the logic of ActivityThread always send onConfigurationChanged no
matter what, not all do.

This CL patches the logic deciding whether or not to send
onConfigurationChanged to act as if the activity specified that it
would handle uiMode changes so that onConfigurationChanged will
always be sent as expected.

Bug: 274944389
Bug: 295876429
Bug: 294255156
Test: atest CtsWindowManagerDeviceOther:DockConfigChangeTests --iterations
      Also manually verified on device that configuration changes are
      always sent to a test activity on dock/undock
Change-Id: Ib4dfcf9ce92538b554935de52850c7514875245c