[SB] Mark SignalCallback & SignalControllers as deprecated.

Now that we have Recommended Architecture equivalents of all the
SignalCallback methods, we can mark the callback and all the controllers
that invoke the callback as deprecated.

Bug: 291321279
Flag: EXEMPT annotation-only change
Test: EXEMPT
Change-Id: I7188b0d8cd95edba2437ec9f3c6a7f4ef7d5d496