[fix] [permissions] Fix role assignment at sign-up (#11045)

In [a previous PR](https://github.com/twentyhq/twenty/pull/11023) I
fixed the issue where users where re-assigned the default role when
signin up using SSO.
The "fix" actually introduced another error, calling
`assignRoleToUserWorkspace` only when a user is signing up to twenty,
forgetting about the case where an existing twenty user signs up to a
different workspace. They should still be assigned the role in that
case.

To fix this and improve clarity, I moved assignRoleToUserWorkspace to
addUserToWorkspace and renamed addUserToWorkspace to
addUserToWorkspaceIfUserNotInWorkspace since this is at each sign in but
does nothing if user is already in the workspace.

I think ideally we should refactor this part to improve readability and
understandability, maybe with different flows for each case: signIn and
signUp, to twenty or to a workspace

packages/twenty-server/src/engine/metadata-modules/permissions/permissions.exception.ts

@@ -24,6 +24,7 @@ export enum PermissionsExceptionCode {
   INVALID_ARG = 'INVALID_ARG',
   PERMISSIONS_V2_NOT_ENABLED = 'PERMISSIONS_V2_NOT_ENABLED',
   ROLE_LABEL_ALREADY_EXISTS = 'ROLE_LABEL_ALREADY_EXISTS',
+  DEFAULT_ROLE_NOT_FOUND = 'DEFAULT_ROLE_NOT_FOUND',
 }
 
 export enum PermissionsExceptionMessage {
@@ -43,4 +44,5 @@ export enum PermissionsExceptionMessage {
   NO_ROLE_FOUND_FOR_USER_WORKSPACE = 'No role found for userWorkspace',
   PERMISSIONS_V2_NOT_ENABLED = 'Permissions V2 is not enabled',
   ROLE_LABEL_ALREADY_EXISTS = 'A role with this label already exists',
+  DEFAULT_ROLE_NOT_FOUND = 'Default role not found',
 }

packages/twenty-server/src/engine/metadata-modules/permissions/utils/permission-graphql-api-exception-handler.util.ts

@@ -25,6 +25,7 @@ export const permissionGraphqlApiExceptionHandler = (
     case PermissionsExceptionCode.ROLE_NOT_FOUND:
     case PermissionsExceptionCode.USER_WORKSPACE_NOT_FOUND:
       throw new NotFoundError(error.message);
+    case PermissionsExceptionCode.DEFAULT_ROLE_NOT_FOUND:
     default:
       throw new InternalServerError(error.message);
   }