Fix for passing snappi api credentials

[selldinesh]

Description of PR

Summary: This pr adds a way of passing credentials for snappi_api based on snappi-sonic.yml file
Fixes # (issue)

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?

To pass username and password for snappi api

How did you do it?

Fetches the username and password from ansible/group_vars/snappi_sonic/snappi-sonic.yml file

How did you verify/test it?

Tested on linux api server

Any platform specific information?

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

Documentation

[selldinesh]

@developfast can you please approve this PR

[rraghav-cisco]

@selldinesh :
No need for "secret_group_vars". It gives KeyError.
We can directly use:
_hostvars[duthost.hostname]['snappi_api_server']['user'].
Same for password.

[rraghav-cisco]

After doing this change, this is able to work.

[selldinesh]

Hi @developfast ,
Request to approve this PR

[rraghav-cisco]

@vmittal-msft : for viz.

[mssonicbld]

The pre-commit check detected issues in the files touched by this pull request.
The pre-commit check is a mandatory check, please fix detected issues.

Detailed pre-commit check results:
trim trailing whitespace.................................................Passed
fix end of files.........................................................Passed
check yaml...........................................(no files to check)Skipped
check for added large files..............................................Passed
check python ast.........................................................Passed
flake8...................................................................Failed
- hook id: flake8
- exit code: 1

tests/common/snappi_tests/snappi_fixtures.py:62:5: F841 local variable 'duthost' is assigned to but never used

flake8...............................................(no files to check)Skipped
check conditional mark sort..........................(no files to check)Skipped

To run the pre-commit checks locally, you can follow below steps:

1. Ensure that default python is python3. In sonic-mgmt docker container, default python is python2. You can run
   the check by activating the python3 virtual environment in sonic-mgmt docker container or outside of sonic-mgmt
   docker container.
2. Ensure that the pre-commit package is installed:

sudo pip install pre-commit

3. Go to repository root folder
4. Install the pre-commit hooks:

pre-commit install

5. Use pre-commit to check staged file:

pre-commit

6. Alternatively, you can check committed files using:

pre-commit run --from-ref <commit_id> --to-ref <commit_id>

[mssonicbld]

Cherry-pick PR to 202405: #13286