[BUG] Solved the name inconsistancy bugs for ChatAgent

[FUYICC]

Description

Renaming model to model_type in ChatAgent

#337

Motivation and Context

#337

• I have raised an issue to propose this change (required for new features and bug fixes)

Types of changes

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• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds core functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Documentation (update in the documentation)
• Example (update in the folder of example)

Implemented Tasks

• Subtask 1
• Subtask 2
• Subtask 3

Checklist

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• I have read the CONTRIBUTION guide. (required)
• My change requires a change to the documentation.
• I have updated the tests accordingly. (required for a bug fix or a new feature)
• I have updated the documentation accordingly.

[lightaime]

The PR looks good. There are some missing places. I just fixed it. Thanks @FUYICC! BTW, next time you can clone the original repo directly instead of forking it since some tests will fail by forking due to the github secretes.