Feature request: allow enemies to use Praise Self with filters

It would be really cool to allow enemies to transmit Praise Self messages using IFF filters, essentially taunting the player after killing one of their allies, like this:

```$Name: Praise Self
$Message: XSTR("A proper fate for a coward!", -1)
+Persona: Wingman V1
+Avi Name: Head-VP2
+Wave Name: V1_praiseself_hostile.wav
$Filter by sender:
+Team: Neutral
+Team: Hostile
```