Properly format PMP replies - #1479

Description

Replying to a PMP now displays the PMP's name instead of the underlying displayname.

Part of #1279

Considerations

• The reply does not indicate that the message author is a PMP. This could be used for impersonation. However, it's unlikely that someone would not notice that the message is not coming from a PMP, given that it is indicated on the actual message.
• Currently does not implement Add PMP name colors #1462, once one of these two PRs is merged the other will have to add a fix. (Stacked PRs pls 🥺)

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings

AI disclosure:

• Partially AI assisted (clarify which code was AI assisted and briefly explain what it does).
• Fully AI generated (explain what all the generated code does in moderate detail).