C2LC-254: Avoid playing sounds before they are loaded.

[the-t-in-rtf]

See C2LC-254 for details.

[simonbates]

Thanks Tony. A couple of comments:

• I'm able to reproduce a similar error when triggering playAnnouncement(), so I think we need a check there also; it looks like Player also has a loaded property
  • To reproduce, click one of the commands in the command palette, such as a forward command
• You added the loaded check to playSoundForCharacterState(), which calls playPitchedSample(); I suggest either moving the check to playPitchedSample() or marking playPitchedSample() as internal so that we don't call it directly in the future and get the error again

[the-t-in-rtf]

I moved the check for the sampler closer to the usage of triggerAttackRelease. I also added a check for the announcements.