Adds option to switch provider test contract source

lib/tasks/contracts/merge_requests.rake

lib/tasks/contracts/pipeline_schedules.rake

lib/tasks/contracts/pipelines.rake

spec/contracts/provider/helpers/contract_source_helper.rb

spec/contracts/provider/helpers/contract_sources.rb

spec/contracts/provider/helpers/publish_contract_helper.rb

..._helpers/project/merge_request/show/diffs_batch_helper.rb

...lpers/project/merge_request/show/diffs_metadata_helper.rb

..._helpers/project/merge_request/show/discussions_helper.rb

...rs/project/pipeline/index/create_a_new_pipeline_helper.rb

...oject/pipeline/index/get_list_project_pipelines_helper.rb

...t_helpers/project/pipeline/show/delete_pipeline_helper.rb

.../project/pipeline/show/get_pipeline_header_data_helper.rb

...pipeline_schedule/edit/update_pipeline_schedule_helper.rb

...ject/pipeline_schedule/update_pipeline_schedule_helper.rb