Convos do not parse colour and/or control codes properly

**Describe the bug**
Convos do not parse colours and control codes properly. Sometimes what should be bold is plain text and what should be plain text is treated as bold and colours look less "bright".

**To Reproduce**
Steps to reproduce the behavior:
1. Go to any channel
2. Ask a friend to send a message with coloured text and/or with bold, italic, etc.
3. At least the control codes (for bold or italic i.e) aren't always treated properly.

**Expected behavior**
The rendering of the text should be the same as the other IRC clients, where bold is bold, etc.

**Screenshots**
Message with colours and bold text as seen in WeeChat:

The same messages as seen by Convos:

Raw messages on Convos (my WeeChat removes all colours on `bare mode`):

**Environment:**
- OS: Xubuntu 22.04.3 LTS
- Browser : Google Chrome
- Version: Version 119.0.6045.123 (Official Build) (64-bit)
- IRC server software, name and/or version: UnrealIRCd 6.1.2.3

**Additional context**
N/A

Reproduce the issue in a channel by sending coloured, bold, and italic IRC messages, then compare Convos with WeeChat and the raw-message screenshots. Trace the control-code parsing and text rendering entry points; the work is done when colours and formatting consistently match other IRC clients.

Written by the indexing model from the issue text.