Add AiAi overview chips to Launcher

Overview chips are constructed in AiAi and inserted into a Launcher
container (similar to what's done for the SuggestView). This CL
(and its sibling) remove the dependency on the NavBarHint plugin
for chip hint data, and instead obtain the information from AiAi.

BUG: 124390101
Change-Id: I07beb79dba2edaafb231b03e70b647ae211b5c1b