Fix tests and type errors.

The `cast` for the FeatureFlagRouters is necessary for Injector to
correctly resolve and inject instances of the type. The actual type is
`Self | FeatureFlagRouter[...]`, but the usages of the injected type do
not rely on `Self`, which messes up how Injector resolves dependencies.

src/web/Ligare/web/middleware/feature_flags/__init__.py

@@ -74,7 +74,7 @@ def get_config_type() -> type[AbstractConfig]:
     def _provide_feature_flag_router(
         self, injector: Injector
     ) -> FeatureFlagRouter[FeatureFlag]:
-        return injector.get(self._t_feature_flag)
+        return cast(FeatureFlagRouter[FeatureFlag], injector.get(self._t_feature_flag))
 
 
 class DBFeatureFlagRouterModule(FeatureFlagRouterModule[DBFeatureFlag]):
@@ -86,7 +86,9 @@ def __init__(self) -> None:
     def _provide_db_feature_flag_router(
         self, injector: Injector
     ) -> FeatureFlagRouter[DBFeatureFlag]:
-        return injector.get(self._t_feature_flag)
+        return cast(
+            FeatureFlagRouter[DBFeatureFlag], injector.get(self._t_feature_flag)
+        )
 
     @singleton
     @provider
@@ -105,7 +107,9 @@ def __init__(self) -> None:
     def _provide_caching_feature_flag_router(
         self, injector: Injector
     ) -> FeatureFlagRouter[CachingFeatureFlag]:
-        return injector.get(self._t_feature_flag)
+        return cast(
+            FeatureFlagRouter[CachingFeatureFlag], injector.get(self._t_feature_flag)
+        )
 
 
 P = ParamSpec("P")

src/web/test/unit/middleware/test_feature_flags_middleware.py

@@ -94,8 +94,9 @@ def _user_session_app_init_hook(
                 bases=[],
             )
         )
-        application_modules.append(CachingFeatureFlagRouterModule)
-        application_modules.append(FeatureFlagMiddlewareModule())
+        application_modules.append(
+            FeatureFlagMiddlewareModule(CachingFeatureFlagRouterModule)
+        )
 
     def test__FeatureFlagMiddleware__feature_flag_api_GET_requires_user_session_when_flask_login_is_configured(
         self,
@@ -108,8 +109,9 @@ def app_init_hook(
             application_configs: list[type[AbstractConfig]],
             application_modules: list[Module | type[Module]],
         ):
-            application_modules.append(CachingFeatureFlagRouterModule)
-            application_modules.append(FeatureFlagMiddlewareModule())
+            application_modules.append(
+                FeatureFlagMiddlewareModule(CachingFeatureFlagRouterModule)
+            )
 
         openapi_mock_controller.begin()
         app = next(
@@ -142,8 +144,9 @@ def app_init_hook(
         ):
             if not flask_login_is_configured:
                 application_modules.clear()
-            application_modules.append(CachingFeatureFlagRouterModule)
-            application_modules.append(FeatureFlagMiddlewareModule())
+            application_modules.append(
+                FeatureFlagMiddlewareModule(CachingFeatureFlagRouterModule)
+            )
 
         def client_init_hook(app: CreateAppResult[FlaskApp]):
             caching_feature_flag_router = app.app_injector.flask_injector.injector.get(
@@ -363,8 +366,9 @@ def app_init_hook(
         ):
             if not flask_login_is_configured:
                 application_modules.clear()
-            application_modules.append(CachingFeatureFlagRouterModule)
-            application_modules.append(FeatureFlagMiddlewareModule())
+            application_modules.append(
+                FeatureFlagMiddlewareModule(CachingFeatureFlagRouterModule)
+            )
 
         openapi_mock_controller.begin()
         app = next(