Thor High-Impact Payload weapon has no launch sound

[Joshua-Leibold]

This weapon has bugged me for a long time but I wasn't able to place my finger on it. Turns out, it straight up has no launch sound which is especially strange for a unit as "heavy" as the thor. You'd expect something

The boring solution is to simply do something like re-use the existing launch asset for the Thor's other AA attack

<!-- Actors -->
<CActorAction id="ThorAALanceAttack">
      <LaunchAssets Sound="Thor_AntiAirAttackLaunch"/>
  </CActorAction>

However, I would much prefer that the weapon have a sound clearly distinguishable from other weapons or impacts (my current main explanation for why the weapon has no sound is that somebody placeholder-disabled it and moved that sound to the anti-mutalisk Javelin weapon since the Javelin weapon's corresponding unused sound is just the viking anti-air attack which is not great for fight readability given vikings don't have a splash attack).

The Warhound's unused attack sound comes to mind as being deep and punchy, which I think players would probably like given the Thor's role as a kind of a fantasy unit:

<!-- Actors -->
<CActorAction id="ThorAALanceAttack">
    <LaunchAssets Sound="WarHound_MeleeAttackLaunch"/>
</CActorAction>