Some further ESLint cleanup, remove some unnecessary scripts and lines (#2984)

src/renderer/components/MainPage.tsx

@@ -2,8 +2,6 @@
 // Copyright (c) 2016-present Mattermost, Inc. All Rights Reserved.
 // See LICENSE.txt for license information.
 
-/* eslint-disable max-lines */
-
 import classNames from 'classnames';
 import React, {Fragment} from 'react';
 import type {DropResult} from 'react-beautiful-dnd';