fix: re-set _shard_ready on resume

[Wolfhound905]

Pull Request Type

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

Description

When creating a repeating task that printed each shards' status sometimes a shard would report as not ready even though the console had said the shard was online. This change fixes an issue where a shard's state was not being set to ready after a Reconnect opcode.

Changes

• Added self.state._shard_ready.set() to dispatch_event

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