Fix PR review comments on SCIM surfaces

- Return valid JSON (null) in `prb scim view --json` when no
  SCIM configuration exists
- Remove organization ID from MCP not-found error to prevent
  identifier disclosure in multi-tenant paths
- Use nullable GID refs for bridge_id and connector_id in
  MCP specification for correct generated ID typing

Signed-off-by: Émile Ré <emile@getprobo.com>

pkg/server/api/mcp/v1/schema.resolvers.go

@@ -5115,7 +5115,7 @@ func (r *Resolver) GetSCIMConfigurationTool(ctx context.Context, req *mcp.CallTo
 	if err != nil {
 		var errNotFound *iam.ErrNoSCIMConfigurationFound
 		if errors.As(err, &errNotFound) {
-			return nil, types.GetSCIMConfigurationOutput{}, fmt.Errorf("SCIM configuration not found for organization %s", input.OrganizationID)
+			return nil, types.GetSCIMConfigurationOutput{}, fmt.Errorf("SCIM configuration not found")
 		}
 		panic(fmt.Errorf("cannot get SCIM configuration: %w", err))
 	}