wasapi2ringbuffer: Implement GstAudioRingBuffer::pause()
WASAPI doesn't support PAUSE so it's not different from Stop().
When pipeline is in paused state, we don't need to waste CPU resource
for feeding silent buffers.
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WASAPI doesn't support PAUSE so it's not different from Stop().
When pipeline is in paused state, we don't need to waste CPU resource
for feeding silent buffers.