Impossible to set ListStyle.none to ChoicePrompt.

[rodolZ80]

Versions

Botbuilder version 4.5.3
NodeJS version 10.16.3

Describe the bug

It is impossible to set ListStyle.none to ChoicePrompt.

To Reproduce

Steps to reproduce the behavior:

1. Set a promptOptions with style as ListStyle.none
   const promptOptions: PromptOptions = { prompt: 'Say a letter' , choices: ['A', 'B'], style: ListStyle.none }
2. Call to a prompt type ChoicePromt with this promptOptions
   return await stepContext.prompt('CHOICE_PROMPT', promptOptions);
3. Options A and B are shown on the screen when they should not be shown.

Expected behavior

Show only the text 'Say a letter' in the screen. (client)

Additional context

The problem is in ChoicePrompt.ts
The style is set to ListStyle.auto by default
Line 67: this.style = ListStyle.auto;
In the onPrompt method if the options.style is false, null undefined or 0 , the assigned style will be the default one (ListStyle.auto).
Line 83: const choiceStyle: ListStyle = options.style || this.style;
The number none is assigned the value 0 .
File prompt.ts Line 17 :

export enum ListStyle {
    /**
     * Don't include any choices for prompt.
     */
    none,

`

[bug]

[mdrichardson]

@rodolZ80 I'm able to reproduce this and will submit a PR to fix it once I have the time to. In the meantime, I was able to get it work doing this:

const choicePrompt = new ChoicePrompt(<yourPromptId>);
choicePrompt.style = ListStyle.none;

this.addDialog(choicePrompt);

[mdrichardson]

@rodolZ80 GREAT work tracking down what needed to be fixed. Made for an easy PR.