[SB][RONs] Rename chip resource ID to ongoing_activity_chip_primary.

Because we want to support multiple chips at the same time with RONs,
this proactively re-names the current single chip to be
ongoing_activity_chip_primary. This will let us add an
ongoing_activity_chip_secondary later.

Bug: 364653005
Flag: NONE resource only change
Test: Smoke test of existing ongoing activity chips
Test: atest CollapsedStatusBarFragmentTest
Change-Id: Id3273a03f5b0a1b65e4d25fa74f36ec65690147c