Screenshot Notification Smart Action: AiAi and - Sys UI integration

Create a constant in ContentSuggestionsManager, which will
be used to pass a hardware bitmap to ContentSuggestionsService.
In the presence of this key in the request extras, we skip taking a
snapshot in ContentSuggestionsPerUserService.
Bitmap is extracted from reading this value from extras in
ContentSuggestionsService.

Create ScreenshotNotificationSmartActionsProvider, which is overridden
in GoogleSystemUI.
Calling AiAi is guarded by a device config flag created in cl/277143225.

(cherry picked from commit d2010f26 and c45d86fc)

Test: Manually tested the code in this CL and corresponding change in SystemUIGoogle.
Took a screenshot and verified that AiAi gets invoked and the screenshot notification
shows smart actions.
Ran new tests added in this CL
'atest ScreenshotNotificationSmartActionsTest'
'atest ContentSuggestionsPerUserServiceTest'
Bug: 141634285
Change-Id: I439a4be9aac53fb02b566ae4d438afe3edf2b37a
Merged-In: I439a4be9aac53fb02b566ae4d438afe3edf2b37a