Add some tests to verify Redis DB configuration

[saiarcot895]

Description of PR

Add a test script to check that the redis config for the save setting, database count, and unix socket are correct. This can be extended to check for other config options.

Summary:
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?

This is in response to sonic-net/sonic-buildimage#18979 and sonic-net/sonic-buildimage#18108, where with the database container upgrade to Bookworm, redis DB was configured to save to disk by default. This then caused issues in multi-ASIC setups.

How did you do it?

How did you verify/test it?

Tested on T0 KVM with sonic-net/sonic-buildimage#18979 applied.

Any platform specific information?

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

Documentation

[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...............................................................Passed
check for added large files..............................................Passed
check python ast.........................................................Passed
flake8...................................................................Failed
- hook id: flake8
- exit code: 1

tests/database/test_db_config.py:16:1: E302 expected 2 blank lines, found 1
tests/database/test_db_config.py:24:121: E501 line too long (142 > 120 characters)

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

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>

[saiarcot895]

/azp run Azure.sonic-mgmt

[azure-pipelines]

Commenter does not have sufficient privileges for PR 12877 in repo sonic-net/sonic-mgmt

[saiarcot895]

/azpw run Azure.sonic-mgmt

[mssonicbld]

/AzurePipelines run Azure.sonic-mgmt

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[bingwang-ms]

@saiarcot895 Do we need this PR for release branch?