…14506)

Why I did it
All these 3 services started after swss service, which used to start after interface-config service. But sonic-net#13084 remove the time constraints for swss.

After that, these 3 services has the chance of start earlier when the inteface-config service is restarting the networking service, which could cause db connect request to fail.

How I did it
Delay mux/sflow/snmp timer after the interface-config service.

How to verify it
PR test.
Config reload can repro the issue in 1-3 retries. With this change. config reload run 30+ iterations without hitting the issue.

Signed-off-by: Ying Xie <ying.xie@microsoft.com>