Add `inputHint` to plugin response in `NLP.js` - switches on speech recognition

[nfreear]

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Allow inputHint = 'expectingInput' to be set

• NLP.js :~ `inputHint: 'acceptingInput', -- https://github.com/axa-group/nlp.js/blob/4.14.2/packages/directline-connector/src/directline-controller.js#L147;
• Type :~ https://github.com/microsoft/botbuilder-js/blob/4.13.1/libraries/botframework-schema/src/index.ts#L1986-L1996;
• Schema :~ https://github.com/microsoft/botframework-sdk/blob/main/specs/botframework-activity/botframework-activity.md#input-hint;
• Webchat :~ https://github.com/microsoft/BotFramework-WebChat/blob/v4.13.0/packages/core/src/sagas/speakActivityAndStartDictateOnIncomingActivityFromOthersSaga.js#L32;
• Doc :~ https://github.com/microsoft/BotFramework-WebChat/blob/v4.13.0/docs/SPEECH.md#using-input-hint

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