[python] Update the MultiscaleImage to match somacore API changes
#970
| Job | Run time |
|---|---|
| 6m 57s | |
| 9m 33s | |
| 5m 0s | |
| 13m 20s | |
| 9m 45s | |
| 7m 2s | |
| 5m 14s | |
| 7m 27s | |
| 3m 32s | |
| 7m 28s | |
| 1h 15m 18s |