[MNT] Replace live server calls with mocks in test_run_functions.py

[Jay2006sawant]

Metadata

• Reference Issue: Fixes [MNT] Replace Live Server Calls with Mocks in Unit Tests #1649
• New Tests Added: No (existing tests refactored)
• Documentation Updated: NA
• Change Log Entry: Replace live server calls with mocks in test_run_functions.py

Details

This PR replaces live test-server calls with local mocks/constructs in tests/test_runs/test_run_functions.py as part of #1649.

7 tests converted:

• test_format_prediction_classification_no_probabilities — direct OpenMLClassificationTask construction instead of get_task()
• test_format_prediction_classification_incomplete_probabilities — same
• test_format_prediction_task_without_classlabels_set — same
• test_format_prediction_task_learning_curve_sample_not_set — direct OpenMLLearningCurveTask construction
• test_format_prediction_task_regression — direct OpenMLRegressionTask construction, removed check_task_existence/create_task/publish server logic
• test_list_runs_empty — mocks _perform_api_call to raise OpenMLServerNoResult
• test_get_cached_run — removed @pytest.mark.test_server() (only reads from local static cache)

All 7 tests now run fully offline without hitting any server.