[FIX] Markdown not rendering as preview for threaded messages

[diegolmello]

Proposed changes

Threaded messages shouldn't render all markdown the rules, like mention or links.

Issue(s)

How to test or reproduce

This is how the web does it:

Before	After

There are a few known issues on the screenshot, like not parsing mentions and not rendering custom emojis.

Screenshots

Types of changes

• Bugfix (non-breaking change which fixes an issue)
• Improvement (non-breaking change which improves a current function)
• New feature (non-breaking change which adds functionality)
• Documentation update (if none of the other choices apply)

Checklist

• I have read the CONTRIBUTING doc
• I have signed the CLA
• Lint and unit tests pass locally with my changes
• I have added tests that prove my fix is effective or that my feature works (if applicable)
• I have added necessary documentation (if applicable)
• Any dependent changes have been merged and published in downstream modules

Further comments