Email Header Parser issue t.token_type == 'attrtext'

# Bug report

### Bug description:

```python
t.token_type == 'attrtext'
```
compares t.token_type with 'attrtext', but it has to be
```python
t.token_type = 'attrtext'
```


### CPython versions tested on:

CPython main branch

### Operating systems tested on:

_No response_


### Linked PRs
* gh-150475