Asterisk `*` in KaTeX mode causes Formatting

Description:

A * inside a KaTeX block is still interpreted as bold formatting by Rocket.Chat although it shouldn't. This causes visible HTML tags in the rendered KaTeX instead of just the formula.

Steps to reproduce:

1. Post a message that contains a KaTeX block with two asterisks, or two KaTeX blocks with one asterisk, e.g. $a*b*c=d$

Expected behavior:

Only the formula should be visible, rendered in KaTeX: a*b*c=d. Asterisks inside KaTeX should not be treated as bold formatting.

Actual behavior:

The Asterisks are interpreted as formatting marks, and the rendered KaTeX formula contains HTML tags instead of just the formula:

a<spanclass="copyonly">∗</span><strong>b</strong><spanclass="copyonly">∗</span>c=d

Server Setup Information:

Version of Rocket.Chat Server: 3.0.12
Operating System: Debian 10
Deployment Method: tar
Number of Running Instances: 5
DB Replicaset Oplog: enabled
NodeJS Version: 12.16.3
MongoDB Version: 4.0.18

Client Setup Information

• Desktop App or Browser Version: Firefox 75.0
• Operating System: Arch Linux

Start with the reported message $a*b*c=d$ in a KaTeX block and compare its rendered output with the expected formula-only result. Trace the message formatting and KaTeX rendering path to find where asterisks are interpreted; done means asterisks remain part of the formula without visible HTML formatting tags.