Handle alternative form VVM SMS as legacy notification if the account is not activated yet.

On VVM3 if subscription failed, the alternative form SMS will still be sent by the carrier. In this state dialer should fallback to legacy voicemail notification.

TEST=manual - disable auto subscription in code, check legacy voicemail notification functionality.
Bug: 109896901
Test: manual - disable auto subscription in code, check legacy voicemail notification functionality.
PiperOrigin-RevId: 200113818
Change-Id: I55b70e7a8b2cd3d8b40864fa03b2ba209037f4e8