HMI ignores initialPrompt in PerformInteraction

[jacobkeeler]

Bug Report

HMI does not speak initialPrompt when provided in VR.PerformInteraction (also applies to helpPrompt and timeoutPrompt)

Reproduction Steps

1. Send PerformInteraction with MANUAL_ONLY and initialPrompt included

Expected Behavior

TTS component speaks initialPrompt when the interaction begins

Observed Behavior

TTS component ignores initialPrompt

Browser & Version Information

• Browser and Version: Chrome
• RPC Sent:

{"initialText":"text","interactionMode":"MANUAL_ONLY","interactionChoiceSetIDList":[1],"initialPrompt":[{"text":"initially","type":"TEXT"}]} 

• Generic HMI Version: master
• Testing Against: RPC Builder JS

[jacobkeeler]

Note that this might factor into #496, since this uses VR.PerformInteraction. Unfortunately some of the TTS information is provided in the VR interface here, so we should try to support this in some way