fix(audio): clear input device IDs if getUserMedia fails

Stored input device IDs are not cleaned up whenever getUserMedia fails
with `NotFoundError` (i.e.: device not found). This causes a couple of
issues whenever skipEchoIfPreviousDevice is enabled:
  - An unnecessary error screen if the user retries audio from scratch
    (it should just go straight to the audio settings modal)
  - A retry loop if no other devices are present in the system

Guarantee that stored input device IDs are cleared up whenever
getUserMedia fails with error name `NotFoundError`. This both the retry
loop and the unnecessary error screen.

bigbluebutton-html5/imports/ui/services/audio-manager/index.js

@@ -432,6 +432,8 @@ class AudioManager {
           break;
         case 'NotFoundError':
           errorPayload.errCode = AudioErrors.MIC_ERROR.DEVICE_NOT_FOUND;
+          // Reset the input device ID so the user can select a new one
+          this.changeInputDevice(null);
           logger.error({
             logCode: 'audiomanager_error_device_not_found',
             extraInfo: {