Bubble v2 changes.

- Only show bubble for outgoing, active and background call. (Before: show bubble when is in call)
- Show "Call ended" and hide bubble only when there is no outgoing, active or background call. (Before: show "Call ended" for all real call disconnection like one call in conference)
- Don't show "Call ended" but only hide bubble when Duo upgrade is accepted/declined. We show bubble for Duo upgrade since the call is still connected. The solution doesn't work for fallback upgrade on pre-ODR device (so "Call ended" still shows).

Bug: 67605985
Test: NewReturnToCallControllerTest
PiperOrigin-RevId: 179636643
Change-Id: I5d1f6e812c94108228757af89e33d4c496beb735