[SNMP][IPv6]: Skip SNMP IPv6 related tests in 202211 branch. (#9630)

What is the motivation for this PR?
Issue sonic-net/sonic-buildimage#16165

Changes added in the PR sonic-net/sonic-buildimage#15487 to support SNMP over IPv6 does not handle if mgmt IP address is obtained via DHCP.

How did you do it?
Skip the sonic-mgmt SNMP IPv6 related tests in 202211 so that the sonic-net/sonic-buildimage#15487 can be reverted.

tests/common/plugins/conditional_mark/tests_mark_conditions.yaml

@@ -1002,6 +1002,18 @@ show_techsupport/test_techsupport.py::test_techsupport:
 #######################################
 #####            snmp             #####
 #######################################
+snmp/test_snmp_link_local.py:
+  skip:
+    reason: "SNMP over IPv6 support not present in 202211 branch."
+    conditions:
+      - "branch in ['202211']"
+
+snmp/test_snmp_loopback.py:
+  skip:
+    reason: "SNMP over Loopback IPv6 support not present in 202211 branch."
+    conditions:
+      - "branch in ['202211']"
+
 snmp/test_snmp_pfc_counters.py:
   skip:
     reason: "M0/MX topo does not support test_snmp_pfc_counters"