Bug: Invalid regular expression exception for emoji replacement in Firefox

Steps to reproduce the behavior

1. Go to the root path of the web server, i.e. localhost:8000
2. See a blank page and an error.

Expected behavior

I see the welcome screen.

Edition and Platform

• Edition: Personal Server
• Version: 7.4.3
• Browser and OS: Firefox 68, Ubuntu 20.04

Symptom

Loading the main page causes a syntax error while parsing the main.js bundle due to an illegal regular expression.

SyntaxError: invalid identity escape in regular expression

Root cause

This is due to an illegal regular expression escape used here:

https://github.com/mattermost/focalboard/blob/v7.4.3/webapp/src/blocks/boardView.ts#L62

Proposal

A code search suggests that sortBoardViewsAlphabetically is not meaningfully used in the codebase; it only has callsites in unit tests.

It seems that it was previously used in webapp/src/components/sidebar/sidebarBoardItem.tsx, however as of aa540e73ce669a1acd491a5edd7d55199ef1b87c, its use was decommissioned and the original utility was not removed.

Removing this function altogether remediates the SyntaxError issue in my local environment. I propose this method and associated unit tests simply be removed.