PCloudStimBuff: Call stop=>start in destroyAttachedStimBuff

This ensures that we can avoid races when adding and removing
stimbuffs to a stimproducer.

At least in theory. I can think of some ways in which this current
design may result in races or other bad conditions.

stimBuffApis/livoxGen1/pcloudStimulusProducer.cpp

@@ -210,6 +210,8 @@ void PcloudStimulusProducer::destroyAttachedStimulusBuffer(
 {
 	if (!buffer) { return; }
 
+	this->stop();
+
 	// Clear specialized buffer pointers if they match
 	if (meshStimulusBuffer == buffer)
 		{ meshStimulusBuffer.reset(); }
@@ -220,6 +222,8 @@ void PcloudStimulusProducer::destroyAttachedStimulusBuffer(
 
 	// Call base class implementation to remove from attachedStimulusBuffers
 	StimulusProducer::destroyAttachedStimulusBuffer(buffer);
+
+	this->start();
 }
 
 std::shared_ptr<StimulusBuffer>