[SB][RONs] Move ongoing activity chip binding to separate binder class.

Because we want to support multiple chips at the same time with RONs,
this proactively moves the chip binder logic to a separate binder class
so we can re-use it for both the primary and secondary activity chips.

Bug: 364653005
Flag: EXEMPT refactor
Test: Smoke test of existing ongoing activity chips
Change-Id: I190abd2b6f7f712755110dd297b4d1115e14a1e6