Return conflict when removing a referenced person

Deleting a profile still referenced elsewhere (for example as an
asset owner) surfaced an internal error. PostgreSQL reports ON DELETE
RESTRICT blocks as SQLSTATE 23001, not 23503; map both in profile
delete and propagate ErrProfileInUse through removeUser as CONFLICT.

Signed-off-by: Ludovic Vielle <ludovic@probo.com>

pkg/server/api/connect/v1/profile_resolvers.go

@@ -145,6 +145,10 @@ func (r *mutationResolver) RemoveUser(ctx context.Context, input types.RemoveUse
 			return nil, gqlutils.Conflictf(ctx, "cannot remove last active owner")
 		}
 
+		if _, ok := errors.AsType[*iam.ErrProfileInUse](err); ok {
+			return nil, gqlutils.Conflictf(ctx, "cannot remove person: referenced by other resources")
+		}
+
 		r.logger.ErrorCtx(ctx, "cannot remove user from organization", log.Error(err))
 
 		return nil, gqlutils.Internal(ctx)