Enhance GainMeter and StepSequencer components with track gain restoration functionality

Commit notes

This commit introduces a new feature in the GainMeter component to listen for track gain restoration events, allowing the volume to sync when gains are restored. Additionally, the StepSequencer component is updated to handle track gains when loading user patterns, ensuring that gain nodes are created before restoring gains. The PatternEngineProvider and SequencerProvider are also modified to support track gains and groove settings, improving the overall functionality and user experience in managing audio settings within the sequencer.