Alexa Reprompt and EmptyMessage bug

[ihmaws]

Describe the bug

1. When using an Alexa skill, the response provided by QnABot does not include a reprompt
2. When using an Alexa skill, an error is thrown when QnABot doesn't know the answer

To Reproduce

1. Ask Alexa a valid question and wait for a response--no reprompt will be heard (if not using an Alexa device, view response object in skill tester)
2. Ask Alexa an invalid question, instead of responding with no_hits, Alexa errors out

Expected behavior

1. Alexa should reprompt if no user interaction
2. Alexa should respond with no_hits

Please complete the following information about the solution:

• [v5.3.1] Version: [e.g. v0.0.1]
• [us-east-1] Region: [e.g. us-east-1]
• [N] Was the solution modified from the version published on this repository?
• [N/A] If the answer to the previous question was yes, are the changes available on GitHub?
• [N/A] Have you checked your service quotas for the sevices this solution uses?
• [Y] Were there any errors in the CloudWatch Logs?

ERROR Invoke Error
{
"errorType": "TypeError",
"errorMessage": "Cannot read properties of undefined (reading 'toLowerCase')",
"stack": [
"TypeError: Cannot read properties of undefined (reading 'toLowerCase')",
" at Object.exports.assemble (/var/task/lib/middleware/alexa.js:107:22)",
" at Array.assemble (/var/task/lib/middleware/5_assemble.js:144:27)",
" at async router._walk (/var/task/lib/router/index.js:34:24)",
" at async router._walk (/var/task/lib/router/index.js:35:20)",
" at async router._walk (/var/task/lib/router/index.js:35:20)",
" at async router._walk (/var/task/lib/router/index.js:35:20)",
" at async router._walk (/var/task/lib/router/index.js:35:20)",
" at async router.start (/var/task/lib/router/index.js:14:21)"
]
}

[ihmaws]

Fixed as v5.3.2