[Bug]: agentsets_by_type won't work with duplicate types

### 📝 Description

the function agentsets_by_type(self) in the file agents.py
won't work with duplicate types
it will only store the latest agents_df

### 🔄 Steps to Reproduce

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### 🎯 Expected Behavior

Ideas :
- append into the existing to keep each fixture separate
- append all together
i think the first method is better

### 🚨 Actual Behavior

_No response_

### 🖥️ Python Version

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### Operating System

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### Relevant Packages

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### 📊 Relevant Log Output

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### ➕ Additional Context

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