fix(backend): Unbreak UserIntegrations parsing for missing None values (#9994)

Makes all optional fields on `Credentials` models actually optional, and
sets `exclude_none=True` on the corresponding `model_dump`.

This is a hotfix: after running the `aryshare-revid` branch on the dev
deployment, there is some data in the DB that isn't valid for the
`UserIntegrations` model on the `dev` branch (see
[here](https://github.com/Significant-Gravitas/AutoGPT/pull/9946#discussion_r2098428575)).

### Checklist 📋

#### For code changes:
- [x] I have clearly listed my changes in the PR description
- [x] I have made a test plan
- [x] I have tested my changes according to the test plan:
- [x] This fix worked on the `aryshare-revid` branch:
52b6d9696b

autogpt_platform/backend/backend/data/model.py

@@ -189,7 +189,7 @@ def SchemaField(
 class _BaseCredentials(BaseModel):
     id: str = Field(default_factory=lambda: str(uuid4()))
     provider: str
-    title: Optional[str]
+    title: Optional[str] = None
 
     @field_serializer("*")
     def dump_secret_strings(value: Any, _info):
@@ -200,13 +200,13 @@ class _BaseCredentials(BaseModel):
 
 class OAuth2Credentials(_BaseCredentials):
     type: Literal["oauth2"] = "oauth2"
-    username: Optional[str]
+    username: Optional[str] = None
     """Username of the third-party service user that these credentials belong to"""
     access_token: SecretStr
-    access_token_expires_at: Optional[int]
+    access_token_expires_at: Optional[int] = None
     """Unix timestamp (seconds) indicating when the access token expires (if at all)"""
-    refresh_token: Optional[SecretStr]
-    refresh_token_expires_at: Optional[int]
+    refresh_token: Optional[SecretStr] = None
+    refresh_token_expires_at: Optional[int] = None
     """Unix timestamp (seconds) indicating when the refresh token expires (if at all)"""
     scopes: list[str]
     metadata: dict[str, Any] = Field(default_factory=dict)

autogpt_platform/backend/backend/data/user.py

@@ -124,7 +124,7 @@ async def get_user_integrations(user_id: str) -> UserIntegrations:
 
 
 async def update_user_integrations(user_id: str, data: UserIntegrations):
-    encrypted_data = JSONCryptor().encrypt(data.model_dump())
+    encrypted_data = JSONCryptor().encrypt(data.model_dump(exclude_none=True))
     await User.prisma().update(
         where={"id": user_id},
         data={"integrations": encrypted_data},