DO NOT MERGE: [CS] Remove timeout event after first available

Guarantees that timeouts are only delivered if a network never
becomes available. Once a network is available the timeout is
canceled.

Bug: 31402633
Test: all timeout related unit tests pass (new one added)

(cherry picked from commit 681fcda5)

Change-Id: I7cd3086544c881915fc6dbf14b87a24ab0cd8748