fix(tests): Revert oauth_test.py fixture scope changes to fix event loop error

Restores session-scoped fixtures and pytest_asyncio decorators that were
accidentally changed, causing "RuntimeError: Event loop is closed" in
test_authorize_creates_code_in_database. Also regenerates openapi.json.

autogpt_platform/backend/backend/api/features/oauth_test.py

@@ -20,6 +20,7 @@ from typing import AsyncGenerator
 
 import httpx
 import pytest
+import pytest_asyncio
 from autogpt_libs.api_key.keysmith import APIKeySmith
 from prisma.enums import APIKeyPermission
 from prisma.models import OAuthAccessToken as PrismaOAuthAccessToken
@@ -38,13 +39,13 @@ keysmith = APIKeySmith()
 # ============================================================================
 
 
-@pytest.fixture
+@pytest.fixture(scope="session")
 def test_user_id() -> str:
     """Test user ID for OAuth tests."""
     return str(uuid.uuid4())
 
 
-@pytest.fixture
+@pytest_asyncio.fixture(scope="session", loop_scope="session")
 async def test_user(server, test_user_id: str):
     """Create a test user in the database."""
     await PrismaUser.prisma().create(
@@ -67,7 +68,7 @@ async def test_user(server, test_user_id: str):
     await PrismaUser.prisma().delete(where={"id": test_user_id})
 
 
-@pytest.fixture
+@pytest_asyncio.fixture
 async def test_oauth_app(test_user: str):
     """Create a test OAuth application in the database."""
     app_id = str(uuid.uuid4())
@@ -122,7 +123,7 @@ def pkce_credentials() -> tuple[str, str]:
     return generate_pkce()
 
 
-@pytest.fixture
+@pytest_asyncio.fixture
 async def client(server, test_user: str) -> AsyncGenerator[httpx.AsyncClient, None]:
     """
     Create an async HTTP client that talks directly to the FastAPI app.
@@ -287,7 +288,7 @@ async def test_authorize_invalid_client_returns_error(
     assert query_params["error"][0] == "invalid_client"
 
 
-@pytest.fixture
+@pytest_asyncio.fixture
 async def inactive_oauth_app(test_user: str):
     """Create an inactive test OAuth application in the database."""
     app_id = str(uuid.uuid4())
@@ -1004,7 +1005,7 @@ async def test_token_refresh_revoked(
     assert "revoked" in response.json()["detail"].lower()
 
 
-@pytest.fixture
+@pytest_asyncio.fixture
 async def other_oauth_app(test_user: str):
     """Create a second OAuth application for cross-app tests."""
     app_id = str(uuid.uuid4())