Remove ProspectiveParachainsMode usage in backing subsystem
#14043
| Job | Run time |
|---|---|
| 43s | |
| 1m 1s | |
| 37m 28s | |
| 32m 34s | |
| 26m 48s | |
| 25m 24s | |
| 7m 52s | |
| 37m 19s | |
| 25m 30s | |
| 27m 27s | |
| 25m 17s | |
| 28m 15s | |
| 1s | |
| 4h 35m 39s |