Downgrade Window JetPack

Add window sidecar aar.
Add settings implementation of SidecarInterface.

Bug: 157477145
Test: use a device with sidecar and not window extensions.
    atest CtsWindowManagerJetpackTestCases:ExtensionTest
Change-Id: Iade7a4ba5a75ba7301cd151b54a95820a3d4bdde