Bugs in abortListening

[JamesBrill]

There are couple of undesirable behaviours in the abortListening method:

• Bug 1 - repro steps:
  1. Start listening
  2. Say something to produce an interim transcript
  3. Before the transcript gets a chance to be finalised, abort listening
  4. Restart listening
  5. Say something else
  6. The interim transcript from step 2 will be replaced by the new transcript. Expected: the new interim transcript should be appended instead
• Bug 2 - repro steps:
  1. Create Dictaphone that aborts listening on unmount (or useEffect cleanup)
  2. Start listening
  3. Say something to produce an interim transcript
  4. Before the transcript gets a chance to be finalised, unmount the component
  5. Remount the component
  6. The interim transcript will still be produced as state from useSpeechRecognition. Expected: the transcript should be reset on remount