fix(#1100): apply language config to Introduction and Conclusion sections

[DAAE-Na-Yunchae]

First, thank you for considering my contribution to the GPT Researcher project. This PR addresses the issue #1100 where the Introduction and Conclusion sections of research reports do not respect the LANGUAGE configuration setting.

Issue Description

When LANGUAGE is set to a non-English value in the configuration (e.g., "japanese"), the Introduction and Conclusion sections remain in English while the rest of the report is generated in the configured language. This creates inconsistency in the report output.

Changes Made

• Modified report generation to pass language configuration to Introduction and Conclusion generation prompts
• Ensures consistent language usage throughout the entire report
• Maintains existing config system behavior while extending its reach to previously missed sections

Testing

I have tested these changes by:

1. Setting LANGUAGE: "japanese" in the configuration
2. Generating a "Detailed" report which includes Introduction/Conclusion sections
3. Verifying that all sections, including Introduction and Conclusion, are now generated in Japanese
4. Confirming that other functionalities remain unaffected
   
   
   

Steps to Reproduce (Original Issue)

1. Set LANGUAGE: "japanese" in the config
2. Run the researcher
3. Select "Detailed - In depth and longer(~5min)" when prompted
4. Observe that Introduction and Conclusion remain in English despite Japanese config

Current Config Example

python
DEFAULT_CONFIG: BaseConfig = {
   "LANGUAGE": "japanese",
   # ... other settings
}

[assafelovic]

Thanks super helpful!