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### Description of PR
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- Please include a summary of the change and which issue is fixed.
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Optimize drop counters test with Python multithreading to reduce its running time.

Summary:
Fixes # (issue) Microsoft ADO 30056122

### Type of change

<!--
- Fill x for your type of change.
- e.g.
- [x] Bug fix
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- [ ] Bug fix
- [ ] Testbed and Framework(new/improvement)
- [ ] New Test case
    - [ ] Skipped for non-supported platforms
- [x] Test case improvement

### Back port request
- [ ] 202012
- [ ] 202205
- [ ] 202305
- [ ] 202311
- [ ] 202405
- [x] 202411

### Approach
#### What is the motivation for this PR?
We wanted to reduce the running time of `drop_packets/test_drop_counters.py`. After the optimization, the running time will decrease from ~180 min to ~140 min.

#### How did you do it?

#### How did you verify/test it?
I ran the updated code and can confirm it's working well. Elastictest [link](https://elastictest.org/scheduler/testplan/67a29b10f5b8ddd54706fc9e?testcase=drop_packets%2Ftest_drop_counters.py&type=console&leftSideViewMode=detail).

T0 & T1 regression tests:
- T0: Elastictest [link](https://elastictest.org/scheduler/testplan/67b7a7e76d2a9cb6b2c91160?testcase=drop_packets%2Ftest_drop_counters.py&type=console)
- T1: Elastictest [link](https://elastictest.org/scheduler/testplan/67b7a7a540469cdb6db51241?testcase=drop_packets%2Ftest_drop_counters.py&type=console)

#### Any platform specific information?

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

### Documentation
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(If it's a new feature, new test case)
Did you update documentation/Wiki relevant to your implementation?
Link to the wiki page?
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#### Why I did it
```
Update submodule sonic-restapi
bd97dfe Fix urllib3 CVE-2021-33503 issue (sonic-net#104)
f159bfa Upgrade the containers to be based on Debian Buster (sonic-net#103)
a1830c1 (origin/201911) Fix OpenAPI spec to be readable by autorest (sonic-net#101)
```

[Submodule]: update sonic-restapi
bd97dfe Fix urllib3 CVE-2021-33503 issue (sonic-net#104)
f159bfa Upgrade the containers to be based on Debian Buster (sonic-net#103)
a1830c1 Fix OpenAPI spec to be readable by autorest (sonic-net#101)
94805a3 Identify and report Vnet GUID for conflicting VNI (sonic-net#99)
4832dfd Static route expiry if not specified as persistent (sonic-net#98)
5cc4358 Add support for overlay ECMP (sonic-net#96)
6822a46 [CI] Set diff cover threshold to 50% (sonic-net#97)
dcc826a Add PR diff coverage (sonic-net#95)
e842c5f Generate code coverage for Unit Tests (sonic-net#94)
f9bbed3 Convert Unit Tests from unittest framework to pytest framework (sonic-net#93)
e466ac2 Reject incorrect CIDR addresses while configuring routes (sonic-net#91)
07cf59d [CI] Set up Azure pipeline (sonic-net#89)
47476ac Upgrade Go version to 1.14 (sonic-net#90)
ee887c7 Added flag to make go/pkg/ folder writable (removable) (sonic-net#87)
6cfc8fe (origin/shilongliu/azp) Default Vrf static route support (sonic-net#85)
d3e8b8e Add BFD config to subinterface and neighbor (sonic-net#68)
8d4fd4a Fix WS-2018-0594 potential non-random UUIDs security issue (sonic-net#78)
fad87fa Update API description for default vrf and ecmp routes (sonic-net#82)

Some of them have been updated in 202012 branch, should be added in 202106 as well.

bd97dfe Fix urllib3 CVE-2021-33503 issue (sonic-net#104)
f159bfa Upgrade the containers to be based on Debian Buster (sonic-net#103)
a1830c1 Fix OpenAPI spec to be readable by autorest (sonic-net#101)
94805a3 Identify and report Vnet GUID for conflicting VNI (sonic-net#99)
4832dfd Static route expiry if not specified as persistent (sonic-net#98)
5cc4358 Add support for overlay ECMP (sonic-net#96)
6822a46 [CI] Set diff cover threshold to 50% (sonic-net#97)
dcc826a Add PR diff coverage (sonic-net#95)

 [Transceiver] Add parser for QSFP-DD cable type and dictionaries for
 QSFP-DD codes (sonic-net#101)

a1830c1761087bdc1f7433ebbb8d0bdc419da0d3 (HEAD -> 201911, origin/master, origin/HEAD, origin/201911) Fix OpenAPI spec to be readable by autorest (sonic-net#101)
94805a39ac0712219f7dc08faa2cfdbf371dd177 Identify and report Vnet GUID for conflicting VNI (sonic-net#99)
4832dfd677de72edc44d4eb8c1b60cfad79a3355 Static route expiry if not specified as persistent  (sonic-net#98)
5cc4358fb67b9e2a0da9a6691064e41f97ebebc2 (master) Add support for overlay ECMP (sonic-net#96)
6822a46197daef060b4d00dba5153b04b163c43f [CI] Set diff cover threshold to 50% (sonic-net#97)
dcc826a1503060b9a07e4510b4f48331c49e87dd Add PR diff coverage (sonic-net#95)
e842c5ff317c67919dcbcab3358143cb9a16c9dd Generate code coverage for Unit Tests (sonic-net#94)
f9bbed3cb86a3bab9a07745096835dbdbe5a4db6 Convert Unit Tests from unittest framework to pytest framework (sonic-net#93)

Signed-off-by: Abhishek Dosi <abdosi@microsoft.com>