Python generator emits trailing commas on enum values, creating tuples instead of strings

### What are you generating using Kiota, clients or plugins?

API Client/SDK

### In what context or format are you using Kiota?

Mac executable

### Client library/SDK language

Python

### Describe the bug

The Kiota Python generator emits trailing commas on `str, Enum` member assignments, which in Python creates **tuples** instead of strings. This causes all enum deserialization via `get_enum_value()` to silently return `None`, since the incoming string from the API response never matches the tuple values stored in the enum.

The command below outputs:
```python
from enum import Enum

class Color(str, Enum):
Red = "red",
Green = "green",
Blue = "blue",
```

In Python, `"red",` is a **tuple** `("red",)`, not the string `"red"`.

All enum deserialization is broken. When `get_enum_value()` receives a string like `"red"` from the API response and tries to match it against enum values, it fails because the enum values are tuples (e.g. `("red",)`), not strings. The method returns `None` instead of the expected enum member.

This affects **every `str, Enum`** generated by the Python generator.

I found one workaround - post-process generated files to strip trailing commas from enum assignments:

```bash
find output/models -name '*.py' \
-exec sed -i 's/^\([[:space:]]*[A-Za-z_]* = ".*"\),$/\1/' {} +
```

### Expected behavior

Expecting to produce this:
```python
from enum import Enum

class Color(str, Enum):
Red = "red"
Green = "green"
Blue = "blue"
```

### How to reproduce

```bash
mkdir -p output
docker run -v ./output:/app/output -v ./openapi.json:/app/openapi.json \
mcr.microsoft.com/openapi/kiota:1.30.0 generate -d /app/openapi.json --language python
cat output/models/color.py
```

### Open API description file

**`openapi.json`:**

```json
{
"openapi": "3.0.3",
"info": { "title": "Minimal Enum Bug Repro", "version": "1.0.0" },
"paths": {
"/items": {
"get": {
"operationId": "getItems",
"responses": {
"200": {
"description": "OK",
"content": {
"application/json": {
"schema": { "$ref": "#/components/schemas/Item" }
}
}
}
}
}
}
},
"components": {
"schemas": {
"Color": {
"type": "string",
"enum": ["red", "green", "blue"]
},
"Item": {
"type": "object",
"properties": {
"name": { "type": "string" },
"color": { "$ref": "#/components/schemas/Color" }
}
}
}
}
}
```

### Kiota Version

1.30.0 (also tried on 1.32 with the same result)

### Latest Kiota version known to work for scenario above?(Not required)

_No response_

### Known Workarounds

_No response_

### Configuration

_No response_

### Debug output

Click to expand log
```

```

### Other information

_No response_

Run the supplied Docker reproduction with the OpenAPI example, then inspect output/models/color.py and the generated Python enum values. Check how get_enum_value() matches API strings against those values; done means generated enum assignments are strings without trailing commas and enum deserialization returns the expected member.

Written by the indexing model from the issue text.