TypeForm: Add covering incremental mode and daemon tests

> **Prerequisite:** This issue applies after PR https://github.com/python/mypy/pull/19596 is merged.

JukkaL recommends that ["one or two incremental and daemon mode tests"](https://github.com/python/mypy/pull/19596#pullrequestreview-3351434400) should be added to cover the TypeForm functionality.
