[chassis]skip test_auto_techsupport.py for multi asic LC (#8171)

What is the motivation for this PR?
The show auto techsupport commands does not work for multi asic devices.
skipping the test till the command failure is fix

How did you do it?
add a check to skip show_techsupport/test_auto_techsupport.py for multi asic cards.

How did you verify/test it?
show_techsupport/test_auto_techsupport.py::TestAutoTechSupport::test_sanity SKIPPED                                                                               [ 25%]
show_techsupport/test_auto_techsupport.py::TestAutoTechSupport::test_rate_limit_interval SKIPPED                                                                  [ 50%]
show_techsupport/test_auto_techsupport.py::TestAutoTechSupport::test_max_limit[techsupport] SKIPPED                                                               [ 75%]
show_techsupport/test_auto_techsupport.py::TestAutoTechSupport::test_max_limit[core] SKIPPED                                                                      [100%]

---------------------------------------------------------- generated xml file: /data/my_mgmt/tests/logs/tr.xml ----------------------------------------------------------
======================================================================== short test summary info ========================================================================
SKIPPED [2] show_techsupport/test_auto_techsupport.py: auto techsupport on multi asic platforms doesnt work
SKIPPED [2] show_techsupport/test_auto_techsupport.py:358: auto techsupport on multi asic platforms doesn't work

Signed-off-by: Arvindsrinivasan Lakshminarasimhan <arlakshm@microsoft.com>

tests/common/plugins/conditional_mark/tests_mark_conditions.yaml

@@ -957,6 +957,19 @@ route/test_static_route.py::test_static_route_ecmp_ipv6:
 #######################################
 #####      show_techsupport       #####
 #######################################
+show_techsupport/test_auto_techsupport.py:
+  skip:
+    reason: "auto techsupport on multi asic platforms doesnt work"
+    strict: True
+    conditions:
+      - (is_multi_asic==True)
+
+show_techsupport/test_auto_techsupport.py::TestAutoTechSupport::test_sai_sdk_dump:
+  skip:
+    reason: "Test supported only on Nvidia(Mellanox) devices"
+    conditions:
+      - "asic_type not in ['mellanox']"
+
 show_techsupport/test_techsupport.py::test_techsupport:
   xfail:
     reason: "Generic internal image issue"