fix import mypy errors (#2407)

# What this PR does

Fix the following pre-existing `import` `mypy` errors (related to
#2392):
```bash
❯ mypy .
settings/prod_without_db.py:4: error: Cannot find implementation or library stub for module named "uwsgi"  [import]
engine/logging/formatters.py:2: error: Skipping analyzing "pythonjsonlogger": module is installed, but missing library stubs or py.typed marker  [import]
engine/logging/formatters.py:2: note: See https://mypy.readthedocs.io/en/stable/running_mypy.html#missing-imports
engine/celery.py:7: error: Skipping analyzing "celery.utils.debug": module is installed, but missing library stubs or py.typed marker  [import]
Found 3 errors in 3 files (checked 595 source files)
```

## Which issue(s) this PR fixes

## Checklist

- [ ] Unit, integration, and e2e (if applicable) tests updated
- [ ] Documentation added (or `pr:no public docs` PR label added if not
required)
- [ ] `CHANGELOG.md` updated (or `pr:no changelog` PR label added if not
required)

engine/pyproject.toml

@@ -32,7 +32,6 @@ disable_error_code = [
     "call-arg",
     "call-overload",
     "has-type",
-    "import",
     "index",
     "misc",
     "name-defined",
@@ -54,6 +53,7 @@ module = [
     # we can slowly either start to add library stubs ourselves, or try and upgrade these libraries to see if
     # a newer version includes type stubs
     "anymail.*",
+    "celery.utils.debug",
     "debug_toolbar.*",
     "django_deprecate_fields.*",
     "django_sns_view.*",
@@ -78,6 +78,7 @@ module = [
     "twilio.*",
     "uwsgidecorators.*",
     "whitenoise.*",
+    "uwsgi.*",
 ]
 ignore_missing_imports = true