Incomplete migration to typed `DexEvent` in `dex_parsers.py`

After the recent refactoring that introduced strongly-typed event handling via the `DexEvent` dataclass and `EventType` enum, not all parsers in `dex_parsers.py` were updated accordingly.

Some parser functions still return legacy `dict`-based event structures instead of the new:

```python
DexEvent(type=EventType.<TYPE>, data=<TypedEvent>)