RootCanal: Increase connection timeout to 3sec

The current  value of 1sec is causing flakiness for avatar tests
due to rare mis-scheduled events. This changes increases the value
as a temporary measure until a proper workaround is put in place.

Bug: 282824672
Test: atest avatar
Change-Id: Idcb053f7720a66beb02a33c68c8ef5f66310cb21