[SB][Notifs] status_bar_ron_chips flag -> status_bar_notification_chips.

Removes "RON" from the flag name and instead makes the flag name more
generic.

Also updates all the "demo RON" code to be "demo notification" instead.

Bug: 364653005
Flag: com.android.systemui.status_bar_notification_chips
Test: all tests under statusbar package
Change-Id: I9174b97369917c33b0dde35a4ff99fb12729df8a