Fixed bugs in new script connection tools.

1. Python sandbox doesn't support nested functions, (to select a function that has a parent function), so I handled this case.
2. There was a bug in the if statement that auto detects/selects the functions from the provided code.

Added 3 functional tests for script connection tools in tests/functional/model/run_connect_model_test.py:

1. test_create_script_connection_tool
2. test_run_script_connection_tool
3. test_run_script_connection_tool_with_complex_inputs

Fixed existing test_run_connect_model in the same file, which tests Slack integration, and connection.

Fixed mocks and added new script tool to tests/unit/agent/agent_test.py::test_create_agent

Added tests/unit/script_connection_test.py, which is specific to new script connection tools.