Simplify system prompts for test dialogue in Chinese and English

Refactor `test_llm_dialogue.py` for improved pipeline creation and streamlined testing

Refactor `test_llm_dialogue.py` to enhance multi-dataset testing for LLM dialogue

Standardize punctuation for system prompts in both Chinese and English text generation modules.

Add dynamic library path setup for `TestLLMDialogue`

Refactor `TestLLMDialogue` to use dynamic LLM model parameters

Add unit tests for LLM dialogue with configurable chat history