[Bug]: Pydantic ValidationError on incoming message messageUpdate

[jerbob92]

Bug Description

I got a messageUpdate event, the event only had attachments and no text, so the text property was missing from the input, causing Pydantic to give a validation error.

Steps to Reproduce

1. Send message with only attachments
2. Update message
3. Get validation error

Expected Behavior

No validation error

Actual Behavior

Validation error

SDK Version

2.0.0a20

Python Version

3.14.2

Additional Context

No response