[ci] Restore mypy checks

[Gold856]

Description

Fixed in https://github.com/robotpy/mostrobotpy/pull/191. Closes #1968.

Meta

Merge checklist:

• [x] Pull Request title is short, imperative summary of proposed changes
• [x] The description documents the what and why
• [ ] If this PR changes behavior or adds a feature, user documentation is updated
• [ ] If this PR touches photon-serde, all messages have been regenerated and hashes have not changed unexpectedly
• [ ] If this PR touches configuration, this is backwards compatible with settings back to v2025.3.2
• [ ] If this PR touches pipeline settings or anything related to data exchange, the frontend typing is updated
• [ ] If this PR addresses a bug, a regression test for it is added

[samfreund]

Still broken

[spacey-sooty]

We might need to wait for a robotpy release