Enable mypy "deprecated" error code

Enable the `deprecated` error code in the mypy configuration so that imports and usages of items marked with `@warnings.deprecated` / `@typing_extensions.deprecated` (PEP 702) are reported at type-check time.

Reference: [https://mypy.readthedocs.io/en/stable/error_code_list2.html#check-that-imported-or-used-feature-is-deprecated-deprecated](https://mypy.readthedocs.io/en/stable/error_code_list2.html#check-that-imported-or-used-feature-is-deprecated-deprecated)

### Scope

- Add `"deprecated"` to `enable_error_code` under `[tool.mypy]` in `pyproject.toml`.
- Run `pants check ::` and fix all newly reported usages of deprecated APIs (migrate to the replacement API, or adjust per-module overrides only when migration is not feasible).

JIRA Issue: BA-7066

Start in pyproject.toml at the [tool.mypy] enable_error_code setting, then run pants check :: to collect newly reported deprecated usages. For each report, inspect the replacement API and migrate it, using a per-module override only when migration is not feasible. Done means the deprecated error code is enabled and pants check :: passes.

Written by the indexing model from the issue text.