Add pathPrefix for modelExplain

[chncaesar]

What changes were proposed in this pull request?

issue #1649

How was this patch tested?

1. Added it case 23_random_forest_model_explain.mlsql; updated linearRegression it case andie_huang_02_train_linear_regression_model.mlsql.
2. Test result
   All it cases runs in yarn-client mode ( hadoop3 ), and successfully finished.

SimpleQueryTestSuite:
22/07/10 11:46:32  INFO TestManager: collect test file: 01_hdfs_command_test.mlsql; matches=.*
22/07/10 11:46:32  INFO TestManager: collect test file: 02_load_csv_file.mlsql; matches=.*
22/07/10 11:46:32  INFO TestManager: collect test file: 03_process_data.mlsql; matches=.*
22/07/10 11:46:32  INFO TestManager: collect test file: 04_save_to_delta.mlsql; matches=.*
22/07/10 11:46:32  INFO TestManager: collect test file: 05_mlsql_assert_test.mlsql; matches=.*
22/07/10 11:46:32  INFO TestManager: collect test file: 06_if_else_test.mlsql; matches=.*
22/07/10 11:46:32  INFO TestManager: collect test file: 07_show_version_test.mlsql; matches=.*
22/07/10 11:46:32  INFO TestManager: collect test file: 08_grammar_analyze_exception_test.mlsql; matches=.*
22/07/10 11:46:32  INFO TestManager: collect test file: 09_run_json_expand_ext.mlsql; matches=.*
22/07/10 11:46:32  INFO TestManager: collect test file: 09_syntax_analysis_ext_test.mlsql; matches=.*
22/07/10 11:46:32  INFO TestManager: collect test file: 10_run_json_expand_ext.mlsql; matches=.*
22/07/10 11:46:32  INFO TestManager: collect test file: 11_json_expand_ext_exception.mlsql; matches=.*
22/07/10 11:46:32  INFO TestManager: collect test file: 13_project_include_test.mlsql; matches=.*
22/07/10 11:46:32  INFO TestManager: collect test file: 13_run_rate_sampler.mlsql; matches=.*
22/07/10 11:46:32  INFO TestManager: collect test file: 14_run_prediction_evaluation.mlsql; matches=.*
22/07/10 11:46:32  INFO TestManager: collect test file: 15_gbt_classifier_test.mlsql; matches=.*
22/07/10 11:46:32  INFO TestManager: collect test file: 16_gbt_regressor_test.mlsql; matches=.*
22/07/10 11:46:32  INFO TestManager: collect test file: 17_discretizer_bucketizer_test.mlsql; matches=.*
22/07/10 11:46:32  INFO TestManager: collect test file: 18_discretizer_quantile_test.mlsql; matches=.*
22/07/10 11:46:32  INFO TestManager: collect test file: 19_feishu_messagge.mlsql; matches=.*
22/07/10 11:46:32  INFO TestManager: collect test file: 20_nesting_variables_across_cells_test.mlsql; matches=.*
22/07/10 11:46:32  INFO TestManager: collect test file: 21_java_udf_compile.mlsql; matches=.*
22/07/10 11:46:32  INFO TestManager: collect test file: 22_scala_udf_compile.mlsql; matches=.*
22/07/10 11:46:32  INFO TestManager: collect test file: 23_random_forest_model_explain.mlsql; matches=.*
22/07/10 11:46:32  INFO TestManager: collect test file: andie_huang_01_train_logistic_regression_model.mlsql; matches=.*
22/07/10 11:46:32  INFO TestManager: collect test file: andie_huang_02_train_linear_regression_model.mlsql; matches=.*
22/07/10 11:46:32  INFO TestManager: collect test file: andie_huang_03_train_automl_extension.mlsql; matches=.*

Run completed in 2 minutes, 31 seconds.
Total number of tests run: 3
Suites: completed 3, aborted 0
Tests: succeeded 3, failed 0, canceled 0, ignored 0, pending 0

Are there and DOC need to update?

No doc changes

Spark Core Compatibility

Spark 2 & 3