Skip keys in table TUNNEL_DECAP_TERM_TABLE for db_cmp

[bingwang-ms]

Description of PR

Summary:
This PR is to skip comparing keys in table TUNNEL_DECAP_TERM_TABLE in test_add_rack.
The keys need to be skipped because the test shutdown a port on the device, and then reload it. Then the entry in table ``TUNNEL_DECAP_TERM_TABLE` for this particular admin down port is lost.
The error message is

11:18:00 helpers.log_msg                          L0060 ERROR  | /var/src/sonic-mgmt/tests/configlet/util/common.py:318:11:18:00 patch_add: app-db.json: Missing key: TUNNEL_DECAP_TERM_TABLE:IPINIP_V6_TUNNEL:fc00::41
11:18:00 helpers.log_msg                          L0060 ERROR  | /var/src/sonic-mgmt/tests/configlet/util/common.py:318:11:18:00 patch_add: app-db.json: Missing key: TUNNEL_DECAP_TERM_TABLE:IPINIP_TUNNEL:10.0.0.32

Related PR sonic-net/sonic-buildimage#18752

Type of change

• Bug fix
• Testbed and Framework(new/improvement)
• Test case(new/improvement)

Back port request

• 201911
• 202012
• 202205
• 202305
• 202311

Approach

What is the motivation for this PR?

This PR is to skip comparing keys in table TUNNEL_DECAP_TERM_TABLE in test_add_rack.

How did you do it?

Add TUNNEL_DECAP_TERM_TABLE:IPINIP_TUNNEL and TUNNEL_DECAP_TERM_TABLE:IPINIP_V6_TUNNEL into the skip list.

How did you verify/test it?

The change is verified on a physical DUT with change in PR sonic-net/sonic-buildimage#18752

collected 1 item                                                                                                                                                                                      

configlet/test_add_rack.py::test_add_rack 
------------------------------------------------------------------------------------------- live log setup --------------------------------------------------------------------------------------------
 ^H ^H ^H ^HPASSED                                                                                                                                                                                          [100%] ^H

Any platform specific information?

No.

Supported testbed topology if it's a new test case?

Not a new test case.

Documentation

[lolyu]

LGTM, thanks for the fix!