Cherry-pick sonic-net/sonic-mgmt#21088
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### Description of PR
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Summary:
This PR is to cancel PFCWD action override at ingress on Th5 platform.
The change is required as PFCWD will work on S/W mode (ACL solution) on
Th5 as a workaround for a known issue.

### Type of change

<!--
- Fill x for your type of change.
- e.g.
- [x] Bug fix
-->

- [ ] Bug fix
- [ ] Testbed and Framework(new/improvement)
- [ ] New Test case
    - [ ] Skipped for non-supported platforms
- [x] Test case improvement


### Back port request
- [ ] 202205
- [ ] 202305
- [ ] 202311
- [ ] 202405
- [ ] 202411
- [ ] 202505

### Approach
#### What is the motivation for this PR?
This PR is to cancel PFCWD action override at ingress on Th5 platform.

#### How did you do it?
Remove the code for overriding PFCWD action in
`tests/pfcwd/test_pfcwd_function.py`

#### How did you verify/test it?
The change is verified on a physical testbed.
```
collected 5 items                                                                                                                                                                                                             

pfcwd/test_pfcwd_function.py::TestPfcwdFunc::test_pfcwd_actions[] 
PASSED                                                                                                                                                                                                                  [ 20%]
pfcwd/test_pfcwd_function.py::TestPfcwdFunc::test_pfcwd_multi_port[] 
PASSED                                                                                                                                                                                                                  [ 40%]
pfcwd/test_pfcwd_function.py::TestPfcwdFunc::test_pfcwd_mmu_change[] 
...
```
#### Any platform specific information?
Th5 platform specific change.

#### Supported testbed topology if it's a new test case?
Not a new test.

### Documentation
<!--
(If it's a new feature, new test case)
Did you update documentation/Wiki relevant to your implementation?
Link to the wiki page?
-->

Description of PR
Backport #21088 to 202505

This PR is to cancel PFCWD action override at ingress on Th5 platform.
The change is required as PFCWD will work on S/W mode (ACL solution) on Th5 as a workaround for a known issue.

Type of change
 Bug fix
 Testbed and Framework(new/improvement)
 New Test case
 Skipped for non-supported platforms
 Test case improvement

Approach
What is the motivation for this PR?
This PR is to cancel PFCWD action override at ingress on Th5 platform.

How did you do it?
Remove the code for overriding PFCWD action in tests/pfcwd/test_pfcwd_function.py

How did you verify/test it?
The change is verified on a physical testbed.

collected 5 items                                                                                                                                                                                                             

pfcwd/test_pfcwd_function.py::TestPfcwdFunc::test_pfcwd_actions[] 
PASSED                                                                                                                                                                                                                  [ 20%]
pfcwd/test_pfcwd_function.py::TestPfcwdFunc::test_pfcwd_multi_port[] 
PASSED                                                                                                                                                                                                                  [ 40%]
pfcwd/test_pfcwd_function.py::TestPfcwdFunc::test_pfcwd_mmu_change[] 
...
Any platform specific information?
Th5 platform specific change.

Supported testbed topology if it's a new test case?
Not a new test.

signed-off-by: jianquanye@microsoft.com

Signed-off-by: vikumarks <vikumar7ks@gmail.com>

Signed-off-by: Alberto Villarreal <alberto.villarreal@keysight.com>

Signed-off-by: opcoder0 <110003254+opcoder0@users.noreply.github.com>

Signed-off-by: selldinesh <dinesh.sellappan@keysight.com>

Signed-off-by: Saravanan <saravanan@nexthop.ai>

Signed-off-by: Guy Shemesh <gshemesh@nvidia.com>

Signed-off-by: Aharon Malkin <amalkin@nvidia.com>

Signed-off-by: Guy Shemesh <gshemesh@nvidia.com>

Signed-off-by: YiFan Wang <yifan@nexthop.ai>

Signed-off-by: Guy Shemesh <gshemesh@nvidia.com>

Signed-off-by: Lakshmi Yarramaneni <lakshmi@nexthop.ai>

Signed-off-by: Yael Tzur <ytzur@nvidia.com>

Signed-off-by: Raghavendran Ramanathan <rraghav@cisco.com>