Uploading a sprite without any sounds while the sound tab is visible crashes sound editor

[kchadha]

Expected Behavior

Editor tabs should not crash.

Steps to Reproduce

1. Open a new project in 3.0
2. Click on the sounds tab
3. Use the 'add sprite' action menu, file upload button to upload a sprite that does not have any sounds (The bananas sprite in the 2.0 library does not have any sounds, so is a good example of this -- export that sprite from 2.0 and upload it into this 3.0 project).
4. Observe that the sound editor crashes.

This also affects restoring the last deleted sprite if the last deleted sprite did not have any sounds.