fix: don't assume msg reference always has msg id

[AstreaTSS]

Pull Request Type

• Feature addition
• Bugfix
• Documentation update
• Code refactor
• Tests improvement
• CI/CD pipeline enhancement
• Other: [Replace with a description]

Description

This is a bit silly - sometimes Discord doesn't provide the message ID for message references... which does sound absurd, granted, but is correctly documented as not doing that in Discord's docs, so this is my fault. At least all the bug does is fill up my logs every once in a while.

Changes

• Use .get to get the message ID for the referenced message, instead of blindly assuming it'll be there.

Related Issues

Test Scenarios

Python Compatibility

• I've ensured my code works on Python 3.10.x
• I've ensured my code works on Python 3.11.x

Checklist

• I've run the pre-commit code linter over all edited files
• I've tested my changes on supported Python versions
• I've added tests for my code, if applicable
• I've updated / added documentation, where applicable