[W]SelfManaged Association device icon

Introduce custom self managed associaiton device icon
API that allow a system app to set the device icon that
displayed in the self managed association dialog and
this device icon will be stored in AssociationInfo

Test: CTS
Bug: 359341630
Flag: android.companion.association_device_icon

Change-Id: Ifa8f3f4016ff748a827e500824c86b95af12b1df