Support both str and int type for slot_id received in pmon API (#5518)

Based on PR sonic-net/SONiC#945, we should return
the sticker/label name on the chassis for the physical slot id
in the get_supervisor_slot PMON API and 'show chassis module status' command.

For Nokia linecards, the sticker label for supervisor is 'A'.
Thus we need to allow for string as possible return value as well - apart for int.

tests/platform_tests/api/test_chassis.py

@@ -530,13 +530,13 @@ def test_get_eeprom(self, duthosts, enum_rand_one_per_hwsku_hostname, localhost,
     def test_get_supervisor_slot(self, duthosts, enum_rand_one_per_hwsku_hostname, localhost, platform_api_conn):
         if chassis.is_modular_chassis(platform_api_conn):
             sup_slot = chassis.get_supervisor_slot(platform_api_conn)
-            pytest_assert(isinstance(sup_slot, int), "supervisor slot is not type integer")
+            pytest_assert(isinstance(sup_slot, int) or isinstance(sup_slot, STRING_TYPE), "supervisor slot is not type integer")
         else:
             pytest.skip("skipped as this test is applicable to modular chassis only")
 
     def test_get_my_slot(self, duthosts, enum_rand_one_per_hwsku_hostname, localhost, platform_api_conn):
         if chassis.is_modular_chassis(platform_api_conn):
             my_slot = chassis.get_my_slot(platform_api_conn)
-            pytest_assert(isinstance(my_slot, int), "supervisor slot is not type integer")
+            pytest_assert(isinstance(my_slot, int) or isinstance(my_slot, STRING_TYPE), "supervisor slot is not type integer")
         else:
             pytest.skip("skipped as this test is applicable to modular chassis only")

tests/platform_tests/api/test_module.py

@@ -331,7 +331,7 @@ def test_get_slot(self, duthosts, enum_rand_one_per_hwsku_hostname, localhost, p
         for i in range(self.num_modules):
             slot_id = module.get_slot(platform_api_conn, i)
             if self.expect(slot_id is not None, "Unable to retrieve module {} slot id".format(i)):
-                self.expect(isinstance(slot_id, int), "Module {} slot id is not correct ".format(i))
+                self.expect(isinstance(slot_id, int) or isinstance(slot_id, STRING_TYPE), "Module {} slot id is not correct ".format(i))
         self.assert_expectations()
 
     def test_get_type(self, duthosts, enum_rand_one_per_hwsku_hostname, localhost, platform_api_conn):