fix: Update speech.ts

[y4my4my4m]

Relates to:

fixes https://github.com/ai16z/eliza/issues/1265

Risks

Background

What does this PR do?

Allows elevenlabs audio to play in discord voice channel

What kind of change is this?

Documentation changes needed?

Testing

Where should a reviewer start?

Detailed testing steps

[y4my4my4m]

Btw i recommend this model for best speed: eleven_flash_v2_5

[monilpat]

Any testing that can be done to confirm this works even just a screenshot?

[y4my4my4m]

@monilpat sorry, are you asking me to provide a screenshot or do you want a 3rd party tester?