Importer gets softlocked when switching from individual to merged layer mode

[RikuTheKiller]

Describe the bug
The importer throws an index out of bounds error at line 234 in AsepriteImporter.cs

To Reproduce
Steps to reproduce the behavior:

1. Import an aseprite file with multiple layers using the individual layer mode.
2. Switch to merged layer mode.
3. Congrats, an error.

This error repeats indefinitely. Even if you delete the meta file. Somehow. :D

Expected behavior
To output a merged sprite without errors.

Screenshots

Desktop:

• OS: Windows 10
• Version: 6000.0.27f1

Additional context
Likely caused by the layer update system.
In debugging, it was indexing "spriteRects" and the other 2 arrays at 234 with invalid indices.
That index stems from the "cells" array having, in my case, a length of 4.
"spriteRects" and the other 2 have a length of 1.
The culprit is most likely the serialized value of "m_AsepriteLayers" from what I can tell.