Add Arista-7060X6-64PE-B-O128S2, Arista-7060X6-16PE-384C-B-O128S2 to GCU (sonic-net#4055)

What I did
Add Arista-7060X6-64PE-B-O128S2, Arista-7060X6-16PE-384C-B-O128S2 to generic_config_updater/gcu_field_operation_validators.conf.json.

This fixes the following failures:

generic_config_updater/test_pfcwd_status.py::test_start_pfcwd[all]
generic_config_updater/test_pfcwd_status.py::test_start_pfcwd[single]
generic_config_updater/test_pfcwd_status.py::test_stop_pfcwd[all]
generic_config_updater/test_pfcwd_status.py::test_stop_pfcwd[single]
How to verify it
Manually ran the generic_config_updater tests

Author: rick-arista

generic_config_updater/gcu_field_operation_validators.conf.json

@@ -31,7 +31,7 @@
                 "th3": [ "Nokia-IXR7220-H3" ],
                 "th4": [ "Nokia-IXR7220-H4-64D", "Nokia-IXR7220-H4-32D" ],
                 "th5": [ "Nokia-IXR7220-H5-64D", "Arista-7060X6-64DE", "Arista-7060X6-64PE", "Arista-7060X6-64PE-C224O8", "Arista-7060X6-64PE-C256S2", "Nokia-IXR7220-H5-64O", "Nokia-IXR7220-H5-32D",
-                         "Arista-7060X6-64PE-B-C512S2", "Arista-7060X6-64PE-B-C448O16", "Arista-7060X6-64PE-B-O128"],
+                         "Arista-7060X6-64PE-B-C512S2", "Arista-7060X6-64PE-B-C448O16", "Arista-7060X6-64PE-B-O128", "Arista-7060X6-64PE-B-O128S2", "Arista-7060X6-16PE-384C-B-O128S2"],
                 "td2": [ "Force10-S6000", "Force10-S6000-Q24S32", "Arista-7050-QX32", "Arista-7050-QX-32S", "Nexus-3164", "Arista-7050QX32S-Q32" ],
                 "td3": [ "Arista-7050CX3-32C-C32", "Arista-7050CX3-32S-C32", "Arista-7050CX3-32S-D48C8", "Arista-7050CX3-32S-C28S4" ],
                 "td4": [ "Nokia-IXR7220-D4-36D" ],