Update fw_testing pytest integration to include using default configuration file

[bevinduckett]

Related Issue(s)	nasa/fprime#4770
Has Unit Tests (y/n)	No
Documentation Included (y/n)	y (code comments)

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Change Description

1. Updated fprime_test_api_session in pytest_integration.py to include default GDS configuration using the ConfigDrivenParser class
2. Updated ConfigDrivenParser class to check the FPRIME_GDS_CONFIG_PATH as part of its default behavior (previously the default file path was included in the class implementation but the environment variable override of that path was only checked in run_deployment.py)

Rationale

The rationale for updating fprime_test_api_session was so that running pytest would pick up the same GDS defaults as fprime-gds - without that feature in my environment, we'd need to have a bunch of different pytest configuration files to ensure the correct dictionary got used for different deployments being tested

Updating the ConfigDrivenParser class was required to avoid environment variable name that could override the default configuration path being specified and handled in multiple locations (previously only in run_deployment.py, but the updates to pytest_integration.py would've also required it)

Testing/Review Recommendations

To test:

1. Create a fprime-gds.yml with unique configuration in a directory with tests, run pytest and verify those settings are picked up
2. Create a fprime-gds.yml in a different location, set the FPRIME_GDS_CONFIG_PATH environment variable with the path to that file, run pytest and verify those settings are picked up
3. Verify pytest uses normal defaults when FPRIME_GDS_CONFIG_PATH is not set and there's no prime-gds.yml in the current directory

Future Work

Note any additional work that will be done relating to this issue.

[thomas-bc]

This blob of change looks like a recent change has been reverted - you likely branched off before it was made. Could we revert it back to the current devel state?