Increase linger delay and test callback timeout

Tests appear to have become much slower on apct in recent runs, although
local runs do not seem to be affected. As a first measure, increase our
timeouts to eliminate flakyness.

Bug: b/111778226
Test: runtest --no-hidden-api-checks -x ConnectivityServiceTest.java
Change-Id: I7a3bfb646eb554bcd9d50d026142f2a2cff74beb