[sonic-snmpagent][sonic-py-swsssdk] Update submodules (sonic-net#4968)

* src/sonic-snmpagent 89b7b2c...c702a57 (7):
  > Revert "[rfc1213] Interface MIB add l3 vlan interfaces & aggregate rif counters (#133)" (#151)
  > Update transceiver info DB key names (#146)
  > Fix LGTM reported alert of PR#141 (#142)
  > [Namespace] Fix interfaces counters in InterfacesMIB RFC 2863 (#141)
  > [Namespace]: Fix SNMP AgentX  socket connection timeout when using Namespace.get_all()  (#140)
  > [rfc1213] Interface MIB add l3 vlan interfaces & aggregate rif counters (#133)
  > Fix undefined variable and warning message (#134)

* src/sonic-py-swsssdk a83366e...2df4f40 (3):
  > Allowing TCP connections with namespace as well. (#81)
  > [port_util] add get_rif_port_map, get_vlan_interface_oid_map (#78)
  > Updates to the namespace API's for test_moduleLoad.py (#77)

Note that sonic-snmpagent submodule update is dependent upon sonic-py-swsssdk update, so updating both submodules in this PR.