Fix AFP reverse mode desync on new sample load (#8158)

Previously, loading a new sample in an AFP instance with reverse enabled would desync the button from the model, such that the button would indicate the sample was reversed despite the new sample not actually being reversed.

This commit fixes this behavior so that samples loaded into an AFP instance with reverse enabled are actually reversed.

plugins/AudioFileProcessor/AudioFileProcessor.cpp

@@ -320,6 +320,7 @@ void AudioFileProcessor::setAudioFile(const QString& _audio_file, bool _rename)
 
 	m_sample = Sample(gui::SampleLoader::createBufferFromFile(_audio_file));
 	loopPointChanged();
+	reverseModelChanged();
 	emit sampleUpdated();
 }