MyPy defaults to ANY if the import path is bad

### Body If you have an import in an if TYPE_CHECKING, mypy may decide to treat it as type(ANY) if it has a problem. **To reproduce:** If you look in [pyproject.toml](https://github.com/apache/airflow/blob/main/pyproject.toml) you can see (currently on L930, but that may change) ``` [tool.mypy] ignore_missing_imports = true ``` If you swap that to `false` and run mypy you'll find over a thousand new errors that should be fixed. **Task:** These can be broken into small bites and fixed in batches, but they should be done and then flip that option to false in pyproject.toml to prevent regression. For some more context and discussion, see the slack thread [here](https://apache-airflow.slack.com/archives/C015SLQF059/p1743790446753629). ### Committer - [x] I acknowledge that I am a maintainer/committer of the Apache Airflow project.