test: Unit Tests for `triton {metrics, config, status}`

[KrishnanPrash]

This PR is raised to address Jira Ticket [DLIS-6264].

Unit tests have been added primarily within triton_cli/tests/test_cli.py for triton metrics, triton config, and triton status.

Brief overview of the tests: For metrics:

• From the test_models repository, mock_llm is loaded.
• Individual inferences are performed on each model
• triton metrics output checked to see if nv_inference_request_success reflects successful inference.

For config:

• From the test_models repository, add_sub and mock_llm are loaded.
• triton config -m model_name is called.
• The name field of the returned json is cross-referenced with the original model_name

For status:

• From the test_models repository, add_sub and mock_llm are loaded.
• triton status is called and verifies from output that the models are live and ready.

Secondary Changes that were made while implementing the tests:

1. Adding grpcio>=1.64.0 to pyproject.toml.
2. Standardizing JSON outputs returned by triton_cli: Triton commands were previously returning keys in single quotes and boolean values as {True, False} instead of {true,false}. This leads to errors when the output is attempted to be parsed as a json.

[rmccorm4]

Nice job merging your first PR already! :rocket: